FIG 4.

Deletion of many genes involved in amino acid biosynthesis partially suppresses zipA1 mutant thermosensitivity. To determine the effects of suppressing zipA1 mutant thermosensitivity, MG1655 (A), WM5337 (MG1655 zipA1) (B), and zipA1 mutants lacking thrA (C), thrB (D), thrC (E), glyA (F), tdcB (G), tdh (H), ilvA (I), kbl (J), ltaE (K), metB (L), metC (M), lysC (N), or argD (O) were grown in LB broth for 2 h at 37°C, at which time cell density was measured by optical density and cell morphology examined by phase-contrast microscopy. Scale bar, 4 μm. Spot assays were used to measure cell viabilities in LB at 30°C (P), 34°C (Q), 37°C (R), and 42°C (S). ND, no dilution.