TABLE 5.
PfruA-cat and PlevD-cat activities measured in wild-type and ccpA and fruA mutant backgrounds under fructose or inulin pulsinga
| Strain and fusion | CAT activity (SD) in cells pulsed with the indicated concentration of fructose or inulin |
||||
|---|---|---|---|---|---|
| 0 mM | 0.05 mM | 3 mM | 5 mM | 7.5 mM | |
| Pulsed with fructose | |||||
| DL1/PfruA-cat | 0.00 (0.00) | 0.03 (0.02) | 0.03 (0.01) | 0.04 (0.02) | 0.16 (0.10) |
| ccpA mutant/PfruA-cat | 0.00 (0.00) | 0.08 (0.09) | 0.16 (0.13) | 0.15 (0.10) | 0.49 (0.08)* |
| DL1/PlevD-cat | 6.13 (1.92) | 7.46 (1.47) | 19.52 (5.38) | 23.07 (2.40) | 34.98 (0.56) |
| ccpA mutant/PlevD-cat | 0.62 (0.12) | 1.03 (0.17) | 17.84 (3.31) | 21.23 (1.19) | 24.84 (0.78) |
| fruA mutant/PlevD-cat | 6.73 (0.19) | 7.40 (0.48) | 26.46 (3.37) | 38.80 (5.20) | 17.45 (2.69) |
| Pulsed with inulin | |||||
| DL1/PfruA-cat | 0.00 (0.00) | 0.33 (0.02) | 0.10 (0.01) | 0.14 (0.02) | |
| DL1/PlevD-cat | 5.28 (2.80) | 5.77 (1.41) | 8.28 (0.44) | 15.23 (2.64) | |
| fruA mutant/PlevD-cat | 6.73 (0.19) | 7.02 (0.85) | 6.65 (0.23) | 6.68 (0.46) | |
The cells were cultured in TV containing 0.5% glucose to an OD600 of 0.2, and then different concentrations of fructose or inulin were added. Cells were incubated for 3 h and harvested for CAT assays as detailed in Materials and Methods. CAT activity is expressed as nmol of chloramphenicol acetylated mg of protein−1 min−1, followed by the standard deviation in parentheses. The data are averages from at least three independent cultures, and all assays were performed in triplicate. The carbohydrate concentration in the growth medium was 0.5% (wt/vol). *, data statistically different from that in the DL1 background, as verified by the Student t test (P < 0.05).