ΔΔCt ¼ Ct target gene−Ct reference gene
Delft tx− Ct target gene−Ct reference gene
Delft t0:
Before the use of the comparative method, it was verified that the
PCR efficiencies of reference and target genes were approximately
equal. Results were expressed as a fold increase (or decrease) of the
target gene during the growth, normalized to the expression of the
reference genes.