Figure 1

A. NO production by SL7838 cell suspensions (A ₆₆₀ , 1.5; glucose-M9 medium) incubated without shaking in the presence of nitrate. NO concentration was determined by the oxy-haemoglobin method [24]; B. NO (green fluorescence) production in SL7838-infected JC cells as measured by DAF-FM diacetate. The mammalian NO synthase inhibitor, L-NAME (20 μM), was added to JC cell growth medium 24 h prior to bacterial infection. SL7838-infected JC cells were supplemented with 0.2 μM NO donor (DEA NONOate) positive control (i), 150 μM NO₃ ^- (ii), or 2 μM NO₂ ^- (iii), or none of these compounds (iv). Uninfected JC cells receiving 150 μM NO₃ ^- also did not generate the fluorescence, as in (iv). The experiment was run in triplicate. Error bars represent STDEV.