TABLE 6.
Effects of RelA′ production on doubling times, FtsZ levels, and cell sizesa
| Strain | Genotype | IPTG concn (μM) | Tdb (min) | [FtsZ]c,f | Long axisd,f (μm) | Short axisd,f (μm) | Vold,e,f (μm3) |
|---|---|---|---|---|---|---|---|
| TB28/pJF118EH | wt/vector | 0 | 61 | ND | ND | ND | ND |
| TB28/pJF118EH | wt/vector | 50 | 59 | 1.0 | 4.1 (0.9) | 1.1 (0.1) | 3.45 (1.1) |
| TB28/pYT11 | wt/Ptac::relA′ | 0 | 62 | ND | ND | ND | ND |
| TB28/pYT11 | wt/Ptac::relA′ | 50 | 103 | 1.3 (0.0) | 1.9 (0.4) | 0.9 (0.1) | 1.0 (0.3) |
| FB30/pFB174/pJF118EH | ΔmreBCD/PBAD::mreBCD/vector | 50 | 76 | 1.1 (0.1) | 4.0 (0.1) | 3.0 (0.6) | 20.2 (10.9) |
| FB30/pFB174/pYT11 | ΔmreBCD/PBAD::mreBCD/Ptac::relA′ | 0 | 68 | ND | ND | ND | ND |
| FB30/pFB174/pYT11 | ΔmreBCD/PBAD::mreBCD/Ptac::relA′ | 50 | 108 | 1.6 (0.1) | 2.3 (0.6) | 1.7 (0.3) | 3.9 (2.6) |
a
Cells were first grown to density in M9-maltose plus 0.5% arabinose. They were then diluted in LB lacking arabinose and containing IPTG as indicated and incubated at 30°C.
b
Td as determined by OD600 measurements.
c
At an OD600 of 0.5, relative FtsZ levels were measured by quantitative Western analyses. Values were normalized to that for TB28/pJF118EH with 50 μM IPTG.
d
Average values for 100 cells at an OD600 of 0.5.
e
TB28 and FB30 cells were considered perfect capsules and prolate spheroids, respectively.
f
Standard deviations are shown in parentheses. ND, not determined.