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. 2020 Aug 24;18(8):e3000757. doi: 10.1371/journal.pbio.3000757

Fig 5. Organosulfur release is associated with nutrient–growth dysregulation.

Fig 5

lys− cells (WY1335) were cultured in lysine-limited (green) or glucose-limited (gray) chemostats at 8-hour doubling time. The concentrations of glucose and lysine in the input fresh minimal medium are marked. (A) Higher percentage of dead cells in lysine-limited chemostats than in glucose-limited chemostats. Live- and dead-cell densities were measured via flow cytometry (Methods, “Flow cytometry”; S6 Data). (B) Higher organosulfur concentrations in lysine-limited chemostats than in glucose-limited chemostats. Organosulfur concentration was measured in terms of GSH equivalents using the met10 bioassay (S5 Fig), with dotted line marking the lower limit of the linear detection range (S6 Data). (C) Adenine-limited ade− cells release organosulfurs at comparable rates as lysine-limited lys− cells. Cells were cultured in chemostats limited for the respective auxotrophic metabolite at 8-h doubling time until a steady state was reached. Release rate was quantified using r = dil × [orgS]ss/[Live]ss (Eq 14 in [30]), where dil is the dilution rate (ln2/8/hour), [orgS]ss is the steady-state organosulfur concentration (measured in terms of GSH equivalents using the met10 bioassay; S5 Fig), and [Live]ss is the steady-state live-cell density. Different colors correspond to experiments done on different days, and each data point represents an independent chemostat (S5 Data). ade−, adenine-requiring mutant; GSH, reduced glutathione; lys−, lysine-requiring mutant; met, methionine-requiring mutant.