TABLE 2.
Differential effects of AHL analogs and AHL synthase of Ecc71 and EC153 on pectate lyase production in AC5094 (AhlI mutant of Ecc71) and AC5111 (AhlI mutant of EC153)
| Bacterial constructa | Relevant characteristicb | AHL | Pel activityc |
|---|---|---|---|
| AHL analog | |||
| AC5094 | AhlI− | 0.07 ± 0.01 | |
| AC5094 | AhlI− | 71AHL | 0.62 ± 0.03 |
| AC5094 | AhlI− | 153AHL1 | 0.57 ± 0.02 |
| AC5094 | AhlI− | 153AHL2 | 0.19 ± 0.02 |
| AC5111 | AhlI− | 0.06 ± 0.01 | |
| AC5111 | AhlI− | 71AHL | 0.20 ± 0.01 |
| AC5111 | AhlI− | 153AHL1 | 0.15 ± 0.01 |
| AC5111 | AhlI− | 153AHL2 | 0.56 ± 0.02 |
| AHL synthase | |||
| AC5094(pDK6) | AhlI− (vector DNA) | 0.08 ± 0.02 | |
| AC5094(pAKC1201) | AhlI− (ahlI71+ DNA) | 0.28 ± 0.03 | |
| AC5094(pAKC1222) | AhlI− (ahlI153+ DNA) | 0.24 ± 0.01 | |
| AC5111(pDK6) | AhlI− (vector DNA) | 0.11 ± 0.02 | |
| AC5111(pAKC1201) | AhlI− (ahlI71+ DNA) | 0.15 ± 0.01 | |
| AC5111(pAKC1222) | AhlI− (ahlI153+ DNA) | 1.05 ± 0.04 |
For the AHL analogs, bacterial cultures were started at a Klett value of ca. 25 in 3 ml of minimal salts medium plus sucrose with or without AHLs and grown at 28°C for 8 h. AHLs were added to a final concentration of 50 μM. Cultural supernatants were used for enzyme assays. For AHL synthase AhlI− mutants, bacteria were grown at 28°C in minimal salts medium plus sucrose (0.5% [wt/vol]), spectinomycin, and kanamycin to a Klett value of ca. 200, and culture supernatants were used for assays.
The relevant DNAs carried by bacteria are given in parentheses.
Expressed as A235/A600 per 30 min. Values are means±standard deviations of three repetitions.