Table 1.

Growth condition-dependent activities of thennr, norC, and nirS promoters

PromoterActivity (Miller units) (SEM) forP. denitrificansa
Wild typeNNR deficientFnrP deficientNirS deficient
O2O2-limNO3NO2O2O2-limNO3O2O2-limNO3O2O2-limNO3
nnr 157 (32.2)170 (4.9)91 (8.9)ND171 (36.0)169 (4.9)107 (14.1)198 (43.0)175 (14.0)97 (8.2)NDNDND
nirS 9 (1.2)46 (21.8)1,076 (104.2)732 (46.2)10 (1.5)10 (1.3)10 (1.2)NDNDND10 (0.9)10 (1.7)10 (1.8)
norC 96 (8.4)142 (69.1)2,371 (302.6)2,100 (198.0)96 (8.9)38 (6.7)184 (24.0)NDNDND106 (8.8)51 (7.8)1,261 (190.2)
  • a The results are the means of at least three independent experiments with the standard errors of the mean (SEM). ND, not determined. Strains were cultured under the following growth conditions: O2, aerobically (flasks filled 1/5 with medium and heavily shaken); O2-lim, semiaerobically (flasks half filled with medium and slowly shaken); NO3 , anaerobically with 100 mM potassium nitrate (flasks completely filled with medium and not shaken); and NO2 , anaerobically with 10 mM potassium nitrite (flasks completely filled with medium and not shaken).