TABLE 2.

Increased sensitivity to paraquat caused by a cyaY mutation^a

Strain	Relevant genotype	Final OD650 in NB containing paraquat atb:
		0 μM	40 μM	80 μM
DM7226	Wild type	0.97 ± <0.01	0.92 ± 0.01	0.92 ± 0.03
DM7225	yggX	0.98 ± 0.01	0.74 ± 0.12	0.25 ± 0.01
DM7644	cyaY	1.03 ± 0.01	0.93 ± 0.02	0.74 ± 0.06
DM7307	apbC	0.97 ± 0.01	0.73 ± 0.04	0.62 ± 0.01
DM7642	apbC cyaY	1.00 ± 0.01	0.37 ± 0.01	0.33 ± 0.01
DN7306	yggX apbC	0.98 ± <0.01	0.35 ± 0.01	0.32 ± <0.01
DM7643	yggX cyaY	1.00 ± 0.01	0.34 ± 0.01	0.31 ± 0.02
DM7641	yggX apbC cyaY	1.00 ± 0.01	0.22 ± 0.01	0.19 ± 0.01

^aOvernight cultures grown in rich media were subcultured with 150 μl added to 5 ml nutrient broth (NB) containing 0, 40, or 80 μM paraquat as indicated. Cultures were incubated with shaking at 37°C, and growth was monitored by measurement of optical density at 650 nm (OD₆₅₀) with a Bausch and Lomb Spectronic 20. The final OD₆₅₀ reported was after 24 h, since absorbance for all strains had reached a plateau by that time. In all cases, loci indicated for relevant genotypes were inactivated by insertion.

^bValues reflect the averages (±standard deviations) of two independent cultures.