Table 1.
Descriptive statistics of reference gene expression across all cultural growth conditions by BestKeeper1
| Gene | GM [Ct] | (min, max) [Ct] | SD [± Ct]2 | (min, max) [x-fold]3 | SD [± x-fold]2 |
| ffh | 19.17 | 18.23, 20.34 | 0.48 | -1.92, 2.25 | 1.39 |
| glnA | 18.62 | 16.37, 21.14 | 1.62 | -3.22, 3.70 | 3.07 |
| gyrA | 20.85 | 18.72, 22.56 | 0.94 | -3.87, 2.98 | 1.92 |
| proC | 21.25 | 19.66, 23.16 | 0.73 | -2.28, 2.69 | 1.66 |
| recA | 20.42 | 19.21, 21.46 | 0.55 | -2.16, 1.96 | 1.47 |
| rho | 20.88 | 18.66, 23.84 | 1.24 | -3.65, 5.62 | 2.35 |
| topA | 20.57 | 17.92, 22.03 | 0.99 | -5.56, 2.56 | 1.98 |
| 16S | 16.62 | 14.49, 18.89 | 1.04 | -2.83, 3.03 | 2.06 |
1Values calculated from 18 samples (6 different culture conditions, each with 3 biological replicates). 2Based on the inspection of the standard deviations (SD), genes can be ranked from the most stably expressed (ffh), exhibiting the lowest SD, to the least stably expressed (glnA), exhibiting the highest SD. Genes with SD [± Ct] > 1 are considered to be inconsistent by BestKeeper. 3The (min, max) [x-fold] values are the x-fold under- or over-expression of samples towards the GM [Ct] according to the equations min [x-fold] = Emin [Ct]-GM [Ct] and max [x-fold] = Emax [Ct]-GM [Ct], respectively, where E is the specific PCR efficiency.
GM [Ct], geometric mean of Ct; (min, max) [Ct], the extreme values of Ct; SD [± Ct], standard deviation of Ct; (min, max) [x-fold], extreme values of expression levels expressed as an absolute x-fold over- or under-regulation coefficient where min [x-fold] = first value and max [x-fold] = last value; SD [± x-fold], standard deviation of the absolute regulation coefficients [7].