FIGURE 8.

Rescue of the null-growth phenotype associated with the functional loss of NfuA by elevated ara-directed expression of NifUS. Top, schematic representation of the genetic organizations of DJ1707, DJ1772, DJ1773, and DJ1791. Bottom, growth of strains when cultured in Burk's medium supplemented with 13 mm ammonium acetate and 20 mm arabinose and cultured under a 40% O₂ atmosphere. NifU and NifS expression are under the control of the ara-regulatory elements, resulting in accumulation of high levels when arabinose is added to the growth medium.