Figure 5

Effect of the limitation of oxygen (A) and the presence of butyrate (B) on the expression of the tagged SPI-1 proteins. Cultures of the tagged strains T-spoE2, T-spaO, T-prgI, T-sptP, T-sipB, and T-sipA were grown in the presence and limitation of oxygen (A), or the absence and presence of 10 mM butyrate (B), as described in Methods and Materials. The values of the relative expression, which are the means from triplicate experiments, represent the ratios for the levels of the tagged protein under the limitation of oxygen conditions to the control condition (i.e. in the presence of oxygen) (A) or the ratios for the levels of the proteins from the bacteria grown in the presence of 10 mM butyrate to those in the absence of butyrate (B).