FIG. 4.

Real-time NASBA of RNA isolated from heat-treated nonviable V. cholerae cells (Cip 106855 O1 Inaba El Tor). (A) NASBA of the toxR and groEL genes in cells treated at 121°C and further incubated for 4 and 24 h at room temperature. (B) NASBA of the groEL gene target in cells treated at 98°C and further incubated for 24 h at room temperature. To confirm that RNA and not DNA was amplified, the nucleic acids were treated with RNase and DNase as described in Materials and Methods. No amplification was detected after RNase treatment. Fluorescence is measured in relative units.