TABLE 3.
Cytoplasmic pH measured in cells of wild type and various mrp constructs after a shift in the external pH from 7.5 to 8.5a
| Concn of indicated salt added (mM) | Cytoplasmic pH of strain:
|
|||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wild type
|
VK1
|
VK1/mrpA
|
VK6
|
VK15
|
VK123
|
VKNI
|
VKNI/mrpA
|
|||||||||
| NaCl | KCl | NaCl | KCl | NaCl | KCl | NaCl | KCl | NaCl | KCl | NaCl | KCl | NaCl | KCl | NaCl | KCl | |
| 100 | 7.5 ± 0.08 | 7.70 ± 0.07 | 7.6 ± 0.15 | 7.8 ± 0.17 | 7.5 ± 0.11 | 7.7 ± 0.04 | 7.60 ± 0.07 | 8.00 ± 0.09 | 7.7 ± 0.05 | 7.90 ± 0.10 | 8.5 ± 0.12 | 8.5 ± 0.13 | 7.6 ± 0.14 | 7.8 ± 0.16 | 7.5 ± 0.15 | 7.7 ± 0.16 |
| 25 | 7.50 ± 0.12 | 7.90 ± 0.11 | 8.2 ± 0.12 | 8.0 ± 0.15 | 7.5 ± 0.14 | 7.9 ± 0.11 | 7.90 ± 0.14 | 8.20 ± 0.11 | 8.00 ± 0.15 | 8.10 ± 0.15 | 8.5 ± 0.11 | 8.5 ± 0.12 | 8.3 ± 0.13 | 8.1 ± 0.14 | 8.2 ± 0.13 | 8.1 ± 0.15 |
| 10 | 7.50 ± 0.09 | 8.10 ± 0.13 | 8.4 ± 0.12 | 8.3 ± 0.15 | 7.8 ± 0.15 | 8.3 ± 0.12 | 8.50 ± 0.08 | 8.50 ± 0.10 | 8.50 ± 0.05 | 8.40 ± 0.15 | 8.5 ± 0.12 | 8.4 ± 0.15 | 8.5 ± 0.11 | 8.4 ± 0.13 | 8.5 ± 0.15 | 8.4 ± 0.14 |
a
All strains were grown at pH 7.0 in TTM medium before being subjected to a sudden shift in the external pH to 8.5 as described under Materials and Methods. The values shown, means ± standard deviations, were measurements taken in duplicate from at least six independent experiments.