Alcohol-induced delay of viability loss in stationary-phase cultures of Escherichia coli.
During prolonged incubation in stationary phase Escherichia coli undergoes starvation-induced differentiation, resulting in highly resistant cells. In rich medium with high amino acid content further incubation of cultures at high cell density leads to the generation of a population of cells no longer able to form colonies. The viability loss is due to some component of spent medium, active at high pH and high cell density, and can be prevented either by keeping the pH close to neutrality, by washing off the nonsalt components of the medium, or by keeping the saturating cell density low. Exposure to short-chain n-alcohols within a specific time window in stationary phase also prevents viability loss, in an rpoS-dependent fashion. The development of stress resistance, a hallmark of stationary-phase cells, is affected following alcohol treatment, as is the response to extracellular factors in spent medium. Alcohols seem to block cells in an early phase of starvation-induced differentiation, most likely by interfering with processes important for regulation of sigma(s) such as cell density signals and sensing the nutrient content of the medium.
Vulić
Marin
M
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Kolter
Roberto
R
D000222:Adaptation, Physiological / Q000187:drug effects; D000438:Alcohols / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000378:metabolism; D002454:Cell Differentiation; D002470:Cell Survival; D003470:Culture Media; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D012808:Sigma Factor / Q000378:metabolism
D000438:Alcohols; D001426:Bacterial Proteins; D003470:Culture Media; D011500:Protein Synthesis Inhibitors; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria