TABLE 3.

Transient and sustained peroxide-mediated oxidative stress does not affect phase variation of agn43

No. of H2O2 pulsesa	Time (h)b	% Lac+c
0d	0	5.2
0d	2	4.8
1	0.16	4.1
1	2	5.9
15	2	4.9

^aAn aliquot of H₂O₂ was added to a growing culture of MV577 (see Materials and Methods).

^bAliquots of the culture were plated at the time indicated, relative to peroxide addition.

^cPercentage of Lac⁺ colonies.

^dUntreated MV577 culture.