FIG. 1.
Growth stage dependence of katG expression in skg mutants. LacZ activity from a chromosomal katG::lacZ translational fusion was measured with ONPG as substrate at the indicated times during growth in PYE. Bars: open, Tn5 control strain SGC125; hatched, skgA::Tn5 strain SGC127; filled, skgB::Tn5 strain SGC126. Values of OD600 for exponential cultures of SGC125, SGC127, and SGC126 were 0.44, 0.55, and 0.29, respectively. We previously showed for wild-type C. crescentus a low and constant expression of katG::lacZ during the entire period of exponential growth in katG fusion strain SGC109. The parental strain for the Tn5 mutants was SGC109. Expon, exponential.