FIG 6.

Mutations in the pst and pho genes suppress phoU depletion lethality, and polyphosphate accumulates upon phoU depletion in Caulobacter crescentus. (A) Locations of Tn5 insertions that suppressed phoU depletion lethality are indicated by arrows. Bars denote directly adjacent but not cooperonic loci. phoU, which was deleted in this background, is shown in black. (B) Light microscopy of the noted strains in the presence and absence of vanillate. Arrows indicate dark granules that may represent polyphosphate (Fig. 7). Bars, 2 μm. (C) Numbers of CFU for the strains indicated, with (left) or without (right) vanillate, are shown, with data points representing the averages of results from two replicates and given as the number of CFU in 1 ml normalized to an OD₆₀₀ of 1.