FIG. 1.

H₂O₂ induces sodA transcription. Wild-type cells grown in M9 minimal medium (optical density at 600 nm of 0.2) were treated with the H₂O₂ concentration (μM) indicated in the abscissa. Samples were collected immediately (<1 min) after the addition of the oxidant. RNA purification, cDNA synthesis, and multiplex PCRs were carried out as described previously (7). An exogenous fragment of the gene (CYP1A) coding for cytochrome P4501A from Liza aurata (9) was coamplified with the target genes and the reference gapA gene. The fluorescence signal of each PCR product was compared to that of CYP1A (noncompetitor heterologous standard). Data were from an average of eight multiplexed PCR amplifications. Values from treated samples were divided by those from the corresponding control (unexposed bacteria). Statistical comparisons were done by an analysis of variance test. Significant increments are indicated by filled-in symbols.