Fig. 1.

pIV-dependent induction of psp expression under different growth conditions. pIV secretin (from pGJ4) induced psp expression in E. coli[MG1655 φ(pspA–lacZ); MVA44] cells grown under aerobic, microaerobic or anaerobic conditions as measured using a β-Gal assay (see Experimental procedures). WT – wild type, MVA44. Insets: Western blot analyses of pIV expression in corresponding cells using antibodies against pIV (α-pIV) (see Experimental procedures). The relative expression levels (in arbitrary units) of pIV were determined as follows: aerobic – 1.57, 2.00, 1.93, 1.84, 2.03; microaerobic – 2.13, 2.27, 2.17, 2.32, 1.77; anaerobic – 1.71, 2.35, 1.82, 2.25, 1.77, and illustrate that the overall variability in pIV expression is ∼1.5-fold.