FIG 4.

Larger AzwK-3b inocula are less inhibited by nitrite. A preculture without manganese or nitrite was grown and sampled in the exponential growth phase (Fig. S4) to prepare inocula from a very early time point in the exponential phase (IT1, panels A and B) and from a later time point (IT2, panels C and D; both sampled in the first third of the exponential phase). These inocula were diluted 1:1 with fresh medium and tested for growth at different nitrite concentrations (see below for color code) without (A, C) or with (B, D) 200 μM Mn^IICl₂ supplement. The nitrite concentrations were as follows: black, control/no nitrite; red, 0.25 mM nitrite; green, 0.5 mM nitrite; blue, 1 mM nitrite; yellow, 2 mM nitrite; magenta, 5 mM nitrite; light blue, 7.5 mM nitrite; and dark red, 10 mM nitrite. Growth curves show the averages and standard deviations over a triplicate analysis (see Materials and Methods).