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Table 2 Promoter activity of nifA::lacZ and nifB::lacZ fusions in H. seropedicae wild-type (SmR1) and glnK mutant (LNglnK) strains

From: Role of PII proteins in nitrogen fixation control of Herbaspirillum seropedicae strain SmR1

Strains β-galactosidase Activity [nmol o-nitrophenol/(min.mg protein)]
  Plasmids
  none pPW452
(promoter-less lacZ vector)
pRW1
( nifA :: lacZ )
pEMS140
( nifB :: lacZ )
SmR1 (3 ± 1) × 10 (6 ± 2) × 10 (7 ± 1) × 102 (2.8 ± 0.1) × 103
LNglnK (2.0 ± 0.7) × 10 (4 ± 2) × 10 (6 ± 1) × 102 (2.5 ± 0.3) × 102
  1. H. seropedicae strains carrying the indicated plasmids were grown in NFbHP medium supplemented with 10 mmol/L of NH4Cl under air at 30°C. The cells were then centrifuged, resuspended in NFbHP (nitrogen-free) medium and de-repressed for 7 hours under 1.5% oxygen. β-galactosidase was determined as described. Values are averages of at least three independent experiments ± standard deviation