TABLE 2.

Validation of microarray-based expression profiles by real-time RT-PCR

GeneProduct/functionAntibioticaCondition (MIC, time [min])Relative expression levelb at:Validationc
MicroarrayReal-time PCR
rplFRibosomal protein L6Cm0.25×, 153.87.3Yes
Em0.25×, 151.53.9Yes
Em0.25×, 600.60.7Yes
Gm0.25×, 52.24.3Yes
Gm0.25×, 600.50.3Yes
rbsBRibose ABC transporters; ribose-binding proteinCm0.25×, 153.84.4Yes
Em0.25×, 150.50.3Yes
Em0.25×, 601.71.6Yes
Gm0.25×, 150.40.4Yes
groESClass I heat shock proteinCm0.25×, 150.30.3Yes
Cm0.25×, 600.30.4Yes
Em0.25×, 150.50.3Yes
Em0.25×, 601.60.1No
Gm0.25×, 603.99.8Yes
clpPClass III heat shock proteinCm0.25×, 150.60.6Yes
Gm0.1×, 602.02.3Yes
Gm0.25×, 603.84.0Yes
Gm0.4×, 604.34.7Yes
cspBCold shock proteinCm0.4×, 603.46.5Yes
cspDCold shock proteinEm0.25×, 152.94.4Yes
  • a Cm, chloramphenicol; Em, erythromycin; Gm, gentamicin.

  • b Values shown are the relative transcript levels of treated sample over untreated sample. The same RNA samples were used for both microarray and RT-PCR experiments. Values more than one indicate induction and values less than one indicate repression in the antibiotic-treated samples.

  • c “Yes” indicates validation of microarray data of up- or downregulation.