Fig. 3From: Increased production of periplasmic proteins in Escherichia coli by directed evolution of the translation initiation regionTime-course analysis of β-lactamase production. a An illustration of the experimental workflow used. b At each time point, a volume of cells was extracted, then separated by SDS-PAGE and immuno-blotted with antisera to β-lactamase. Band intensities were obtained from immuno-blots by densitometric analysis and normalised to the highest-valueBack to article page