Table 2. C T values and normalized nifH expression ratios.
| Gut region | Threshold nifH cycle valuesa CT(target, nifH) | Threshold rpoB cycle values CT(ref, rpoB) | Normalized nifH expression ratio in reference to rpoBb 2−ΔΔCT |
|---|---|---|---|
| FG | 33.4 (0.46) | 29.7 (0.18) | 1.00 |
| MG | 30.37 (3.40) | 28.92 (1.94) | 4.76 |
| AHG | 27.27 (0.81) | 28.31 (0.88) | 26.72 |
| PHG | 32.13 (1.41) | 29.71 (0.59) | 2.43 |
Abbreviations: AHG, anterior hindgut foregut; CT, threshold cycle; FG, foregut; MG, midgut; niFH, nitrogenase gene; pf, detection threshold; PHG, posterior hindgut; rpOB, RNA polymerase β-subunit.
a
CT values for nifH and rpoB representing 100 ng of total RNA isolated from the four gut regions of the gut of Odontotaenius disjunctus; within parenthesis is the standard deviation values for the assay in three beetles.
b
2−ΔΔCT is the expression ratio of the nitrogenase gene nifH, normalized in reference to the single copy bacterial gene of the rpoB. Expression ratios for all regions are expressed relative to the lowest values detected CT values (from the FG).