FIG. 2.

Effect of hns mutation on the expression of acid resistance in E. coli MC4100. Cultures were diluted 1:1,000 and were grown in LB medium. Results were taken from a single experiment performed in triplicate. The percentage of acid resistance was determined along the growth curve for strains MC4100 (circles), MC4100 hns (squares), MC4100 rpoS (diamonds), and MC4100 hns rpoS (triangles). Specific acid resistance and optical densities (OD) at 600 nm are indicated by open and closed symbols, respectively.