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Figure 1 | BMC Genomics

Figure 1

From: Small noncoding RNA GcvB is a novel regulator of acid resistance in Escherichia coli

Figure 1

Regulatory role of the small noncoding RNA GcvB in acid resistance in Escherichia coli. (A) MG1655-K12 wild type strain (wt) and various deletion mutants were grown in Luria Broth broth (pH 7.0) for 5 hr at 37°C. Cells were acid shocked at pH 2.0 for 30 min, and then neutralized by adding alkalinized LB (pH 9.3). Cells were allowed to grow for an additional 3 hrs before measurement of optical density at 600 nm (OD600). Two-tailed paired t tests were employed to compare each mutant with the wt in terms of acid resistance. (B) Because the gcvB mutant displayed a lower growth rate than the wt (data not shown), percent acid survival was determined to confirm the data of acid recovery measured as OD600. Cell viability was determined by plate counts and percent acid survival was calculated as the number of cfu remaining after the 30 min-acid treatment divided by the initial cfu at time zero (quoted as a percentage). (C) A plasmid expressing GcvB under the control of its native promoter was transformed into a gcvB mutant of E. coli MG1655. The mutant carrying an empty vector was used as a control. Cells were incubated for 5 hrs before being acid challenged for 15 min. Error bars represent standard deviation (* P-value < 0.05).

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