TABLE 2.

Expression ratios of genes involved in detoxification of oxidative stresses identified in S. mutans microarray analysis

Gene name	Function	ΔspxA strain		ΔspxB strain		Δspx ΔspxB strain
		Arraya	RT-PCR	Array	RT-PCR	Array	RT-PCR
trxA	Thioredoxin	ND	1.967	0.639	1.574	0.227	0.134**
trxB	Thioredoxin reductase	0.355	0.800	ND	1.900	ND	0.233**
dpr	Peroxide resistance protein	0.133	0.263*	ND	0.289*	0.198	0.021**
sodA	Superoxide dismutase	0.054	0.058	ND	0.129	0.068	0.004
ahpC	Alkyl hydroperoxide reductase	0.136	0.236***	ND	0.491**	0.072	0.055***
ahpF	Alkyl hydroperoxide reductase	0.167	0.236***	ND	0.542**	0.079	0.060***
gor	Glutathione reductase	0.258	0.462*	ND	0.962	0.298	0.104**
tpx	Thiol peroxidase	0.173	0.088***	ND	0.500*	0.069	0.003***
nox	H2O-forming NADH oxidase	0.183	0.284***	ND	0.261***	0.046	0.010***

^aArray data are relative levels of expression compared to expression in S. mutans UA159. RT-PCR data are gene copy numbers relative to those of S. mutans UA159. ND, no significant differences in expression were determined by microarray analysis. *, P ≤ 0.05; **, P ≤ 0.005; ***, P ≤ 0.0005.