Fig 1. Transient heme-iron restriction promotes a cyclical pattern of viability and microevolution during stationary phase.

(A) Schematic representation of environmental heme-iron restriction and extended incubation of stationary phase cultures. (B) Viability was determined every 24 hours for 39 days. Arrow indicates the culture selected for further investigation, termed RM33. Asterisks denote cultures selected for whole genome sequencing. (C) The sequence reads that exhibit the single nucleotide polymorphism (SNP) are reported as percentage of the total reads for icc on each of the days. The number of sequence reads for each sample were: RM12 (889), RM13 (632), RM32 (938) and RM33 (997). (D) Sanger sequencing electropherograms validate the mutation [Adenine (A) → Thymine (T)].