TABLE 4.

Effects of expR71 or expR153 plasmids on the expression of rsmA71-lacZ fusion in E. coli in the presence of 71AHL (3-oxo-C6-HL), 153AHL1 (3-oxo-C6-HL), or 153AHL2 (3-oxo-C8-HL)

Bacterial constructaRelevant characteristicbAHLβ-Galactosidase activity (Miller units)c
MC4100(pCL1920, pAKC1100)Vector + rsmA71-lacZ548 ± 10
Vector + rsmA71-lacZ+71AHL535 ± 14
Vector + rsmA71-lacZ+153AHL1524 ± 15
Vector + rsmA71-lacZ+153AHL2534 ± 10
MC4100(pAKC936, pAKC1100)expR71 + rsmA71-lacZ1,801 ± 20
expR71 + rsmA71-lacZ+71AHL584 ± 10
expR71 + rsmA71-lacZ+153AHL1574 ± 15
expR71 + rsmA71-lacZ+153AHL21,922 ± 31
MC4100(pAKC937, pAKC1100)expR153 + rsmA71-lacZ6,250 ± 60
expR153 + rsmA71-lacZ+71AHL5,406 ± 25
expR153 + rsmA71-lacZ+153AHL14,682 ± 21
expR153 + rsmA71-lacZ+153AHL21,790 ± 10
  • a Bacteria were grown at 28°C in LB agar supplemented with spectinomycin and tetracycline to a Klett value of ca. 100 and divided into four flasks. Three flasks were used for adding 71AHL, 153AHL1, or 153AHL2 (to a final concentration of 50 μM), respectively, and the other one was used as control (added water). After an additional 3 h of incubation at 28°C, cultures were used for assay.

  • b The relevant characteristics of the genes carried by bacteria are given.

  • c Values are means ± standard deviations of three repetitions.