FIG. 9.
Glutamate- and lysine-dependent acid-resistant systems increase the viability of P-starved cells shifted to anaerobiosis. Strains ENZ535 (wt) (A and B), ENZ1592 (gadA gadBC) (C), ENZ1588 (gadC) (D), ENZ1607 (cadBA) (E), and ENZ985 (rpoS) (F) were inoculated 1:500 (time zero) into MOPS medium with a limited amount of Pi containing 20 mM glucose and 86 mM NaCl or 66 mM NaCl (cultures that were supplemented with glutamate and aspartate). Cultures were incubated with aeration for ∼7 h until the OD600 was ∼0.2 and supplemented with different concentrations (indicated on the abscissa) of glutamate (+ GLU), aspartate (+ ASP), lysine (+ LYS), ornithine (+ ORN), or arginine (+ ARG), and 13-ml fractions were transferred into 15-ml tubes. The numbers of CFU were determined after 7 days of incubation. Most of the data are the means ± standard deviations for two independent cultures representative of several determinations; the exceptions are the data for the cultures with aspartate, ornithine, and arginine, which are data for three independent cultures.