FIG 5.

Effects of pyridoxal-5-phosphate and deletions of thrC or metC in suppressing thermosensitivity of fts cell division mutants. Thermosensitive mutants ftsA12, ftsZ84, fts123, ftsQ1, and ftsK44 (A, D, G, J, and M, respectively) and single deletions of thrC (B, E, H, K, and N) or metC (C, F, I, L, and O) generated in each fts strain background were grown for 1.5 h in LB at the semipermissive temperature of 37°C and examined by microscopy (A to O). After transferring the ftsQ1 and ftsI23 alleles to the MG1655 strain background, fts mutant cells with or without ΔmetC or ΔthrC were spotted on LB or LB with no added NaCl at four different temperatures (P). Five fts mutants were tested for the ability of 1 mM PLP to suppress their thermosensitivity after 22 h of incubation at the temperatures indicated; the ftsQ1 and ftsI23 derivatives shown here are in MC4100, while the others are in MG1655 (Q). To rule out effects due to strain background, derivatives of ftsQ1 or ftsI23 mutants with or without ΔmetC or ΔthrC in either the MC4100 strain background or the MG1655 background were compared for the ability of 1 mM PLP to rescue viability after 20 h of incubation at 42°C (R). ND, no dilution. Scale bar, 4 μm.