FIG. 2.

Resuscitation of copper-induced VBNC E. coli. Cells grown and harvested as described in the text were placed in 0.9% NaCl liquid cultures with (■) or without (⧫) 500 μM CuSO₄. At various times, culturability was quantitated as described in the text. At day 14, VBNC cells were harvested, washed, and suspended in copper-free 0.9% NaCl either undiluted (■), after 25-fold dilution (▴), or after 1,000-fold dilution (●), as described in the text. Culturability was then monitored. Samples lacking detectable culturable cells are plotted on the log scale as 1 CFU per ml. The results presented here are from one of three trials. Bars represent standard errors.