Fig. 4.

ldh copy number (a) and ldh transcripts abundance (b) in the wild type and genetically modified mutants of P. vulgatus. a To estimate the copy number, qPCR was performed to compare chromosomal and plasmid-encoded ldh of the mutant strains with the single-copy chromosomal ldh of the wild type strain. b The relative amount of ldh transcripts was analyzed by RT-qPCR. Experiments shown in a and b were conducted in duplicate using DNA or RNA preparation from three different cultures harvested in the mid-exponential growth phase. ΔCt values were determined by subtracting the average Ct values of the ldh gene (BVU_2499) from the reference gene encoding the ribosomal protein L23 (BVU_0803). Ratios were calculated from ΔΔCt values using the function 2^–ΔΔCt. Standard deviations are indicated by error bars. Gray bars, wild type; white bars, P. vulgatus pMM656_ldhnP; black bars, P. vulgatus pG106_ldhnP