Figure 2.
Growth of E. coli strains on (GlcNAc)2 and cellobiose. E. coli strains XL1-Blue MR (wild type, •), Xm1.4 (transposon mutant, ▴), and Xm1.4:pES1 (transposon mutant harboring the 7.3-kb clone, ○) were tested for their ability to grow on (GlcNAc)2 (solid lines) and cellobiose (dashed lines) as sole carbon sources. Minimal media (M9 salts) supplemented with 0.5 mM thiamine and 0.05% Casamino acids containing either 10 mM (GlcNAc)2 or 10 mM cellobiose were inoculated using a 1:100 dilution of overnight cultures grown in LB. Growth was monitored over the indicated time course by using a Klett photoelectric colorimeter with a no. 54 green filter (550 nm). At the arrow, an aliquot of Xm1.4:pES1 cells [preinduced by growth to mid-logarithmic phase on (GlcNAc)2] was harvested and washed three times with an equal volume of minimal medium and then resuspended in minimal medium containing 10 mM cellobiose.