Nitroreductase activity in N. gonorrhoeae strains. Cell sonicates were tested for their ability to produce a loss of absorbance at 400 nm, indicating a reduction of nitrofurazone by an active nitroreductase. The symbols represent: FA1090 (□); FA1090 extract lacking NADPH (□); and FA1090(M1), an nfsB mutant of FA1090 (□). Samples measured every 30 sec for 10 min. The data represents the average of 7 separate experiments with the error bars representing the standard error.