FIG. 4.

Complementation of the asparagine-auxotrophic phenotype of E. coli ME6279 by expression of asparagine synthetase genes of B. subtilis. E. coli ME6279 cells harboring plasmid pASNB (solid triangles), pASNH (solid squares), pASNO (open circles), pOU71 (solid diamonds), or pYXBB (open diamonds) were precultured in LB with asparagine (50 μg/ml) for 16 h at 37°C with shaking. The cells in each of the precultures were washed once and then inoculated into M9 medium with (left) and without (right) asparagine (50 μg/ml) and allowed to grow at 37°C with shaking. The OD₆₀₀s for cells were monitored at 1-h intervals. Data from a single experiment are presented. The same experiments were repeated at least three times with similar results.