FIG. 1.

Influence of high salinity and iron limitation on the expression pattern of the opuBC, yocC, feuA, and wapA genes. The sigB mutant strain BLOB22 was continuously grown either in synthetic medium with 5 μM FeCl₃ and no extra NaCl added (control condition), in a medium without any extra NaCl or FeCl₃ (iron limitation), or in a high-salinity synthetic medium with 1.2 M NaCl and either 5 μM FeCl₃ (high-salinity growth) or 250 μM FeCl₃ (high-salinity growth with excess iron). Total RNA was prepared from cultures of each of the four different conditions as described in Materials and Methods. RNA samples were electrophoretically resolved on denaturing agarose gels and transferred to nylon membranes. RNA blots were then hybridized with specific, digoxigenin-labeled probes internal to the structural genes of feuA, opuBC, wapA, and yocC. Transcript sizes were estimated based on the relative positions of appropriate size markers.