5-days competition lex-wt

Short-term fitness effects of the SOS response. Frequency of the WT strain in competition with the LexA strain across multiple cycles of competition, in the presence of ciprofloxacin or not. After 16 generations, the WT strain had achieved such a high frequency that it could no longer be accurately measured

Cell density cip doses

Impacts of ciprofloxacin on bacterial population density. Mean (+/- sem; n≥3) density of viable cells in cultures of the WT strain that were grown overnight across a gradient of ciprofloxacin (ug/L)

Mutation rate wt-lex with cip

Mutation rate of WT and LexA in the absence or presence of ciprofloxacin, as calculated using a fluctuation test that measures the rate of mutation to rifampicin resistance. Estimation of mutation rate values (and 95 % confidence intervals) was done using MSS maximum likelihood method from eight independent replicates

MIC wt-lex time

MIC scores (ciprofloxacin concentration in ug/L) in WT and LexA populations that were allowed to evolve for 200 generations in the presence and absence of ciprofloxacin. We also present the date from the ancestor (T0) populations

SOS expression cip doses

Impacts of ciprofloxacin on SOS expression. Mean relative expression (+/- s.e.m; n≥3) of a bioluminescent SOS reporter construct across a gradient of ciprofloxacin (ug/L) in a WTpLex:Lux reporter strain and a WT control lacking the reporter construc

SOS expression cip-no time

Relative expression of a bioluminescent SOS reporter construct in populations of WTpLex:Lux that were allowed to evolve in culture medium lacking ciprofloxacin or containing ciprofloxacin. We measured the expression of populations under the conditions in which they evolved

Fitness wt-lex cip-no ratios

Short-term fitness effects of the SOS response. Competitive fitness of the WT strain relative to the LexA mutant, as measured using overnight competition experiments in the presence of ciprofloxacin or not. Values are the average of 20 independent replicates starting from different WT:LexA frequencies and error bars are SEM