Fig. 1

Effect of glyphosate on the MDK of bacteria treated with ampicillin, ciprofloxacin or kanamycin. Exponentially growing cells (OD₆₀₀\(\sim\) = 0.5) were diluted to approximately \(10^7\) bacteria/ml. 5 mM glyphosate were added to one-half of the cultures and 30 minutes later a final concentration of \(20 \times\) MIC of each antibiotic was added to the cultures. Samples were withdrawn at time 0 and at different time-intervals, depending on the antibiotic treatment. Each point corresponds to the mean of at least three independent experiments ± standard deviation (SD). The fraction of survivors was determined by colony counting on L-agar plates. Left (A, C and E), MG1655; Right (B, D and F), MG1655 \(\Delta {relA}\). p-values were calculated using a pairwise t-test between the antibiotic and antibiotic+glyphosate treatment at each time interval. *** indicates \(p \le 0.001\); ** indicates \(p \le 0.01\); ns, not significant