Fig. 1: Growth curve and lag time of E. coli and V. natriegens during amino acid downshift (AA downshift).
From: Stringent response ensures the timely adaptation of bacterial growth to nutrient downshift
A Illustration of a typical bacterial growth curve of nutrient downshift. B Illustration of the culture-transfer protocol. The bacterial culture of preshift medium was collected by 0.22 µm filter membrane using filtration, washed twice by the postshift medium and then transferred to the postshift medium for culturing. The time cost of the whole culture-transfer process is generally within 3 min. C Growth curve and lag time of wild type E. coli cells during transition from glucose cAA medium (glu+cAA) to amino acid-free glucose minimal medium. D Growth curve and lag time of E. coli relA-deficient mutant during transition from glu+cAA medium to glucose minimal medium. E Comparison of lag time between wild type and relA-deficient E. coli cells during AA downshift. Both glucose (glu) medium and glycerol (gly) medium were used. Error bars are the standard deviations of several biological replicates (glu+cAA to glu: n = 5 and 4 for wild type and relA-deficient strain, respectively; gly to cAA to gly: n = 2 and 3 for wild type and relA-deficient strain, respectively). F The ppGpp pools of E. coli at 0 min, 5 min and 30 min during AA downshift. Error bars are the standard deviations of several biological replicates (n = 3 for relA-deficient mutant; for wild type strain, n = 6, 4 and 4 for 0 min, 5 min and 30 min, respectively. G Growth of wild type and relA-deficient V. natriegens strains after AA downshift (glucose as carbon source). OD600 during AA downshift in this case is automatically monitored by microplate reader. H Comparison of lag time between wild type and relA-deficient V. natriegens cells during AA downshift. Error bars are the standard deviations of several biological replicates (n = 7 and 4 for wild type and relA-deficient strain, respectively). Source data are provided as a Source Data file.
