Figure 1.
Effect of Hfq65 on survival under nutrient limitation and on growth on succinate. (A) Escherichia coli strains AM111(pAHfq) (closed square) and AM111(pAHfq65) (closed triangle) were grown in LB-medium, washed with M9-minimal medium, and then resuspended in M9-minimal medium containing 0.2% glucose to 1 × 109 cells ml−1. The CFU at the indicated times was determined by plating of serial dilutions on LB plates containing kanamycin and chloramphenicol. The experiment was performed in triplicate. The error bars represent standard deviations. The inset shows the concentrations of Hfqwt and Hfq65 at different times after incubation from one representative experiment. At times 48, 72 and 96h aliquots of both strains were withdrawn, and equal amounts of total cellular protein was subjected to western blot analysis using Hfq-specific antibodies as described in Materials and Methods section. Only the Hfq-specific bands are shown. (B) Escherichia coli strains AM111(pAHfq) (closed square) and AM111(pAHfq65) (closed triangle) and AM111(pACYC184) (closed circle) were grown overnight in LB-broth, washed with M9-minimal medium and then resuspended to an OD600 of 0.05 in M9-minimal medium containing 0.2% succinate and 2,2′-dipyridyl (50 μM final concentration). Growth was followed by measuring the OD600 at the times indicated. The result of one representative experiment is shown.