Figure 3

Effect of tannic acid inhibition on amplification curve shape. Left upper panel: amplification profiles obtained from samples with equal starting number of template molecules and increasing inhibitor concentrations. For each inhibitor concentration only an amplification curve was plotted (instead of all 6 replicates). Values over and under triangle indicator (at the upper right of the Fig.) show the lowest and the highest inhibitor concentration used (A). Right upper panel: effect of PCR inhibition on the ratio Log(N _ob /N _exp ) in the presence of equal starting number of template molecules and increasing inhibitor concentration. The ratio Log(N _ob /N _exp ) represents the residues obtained from linear regression of calibration curves where LogN _ob is the number of calculated molecules using Ct method and N _exp is the number of expected molecules. Each symbol represents a single run. The abscisse axis is the mean and the dotted lines are the 95% confidence interval of the Log(N _ob /N _exp ) ratio calculated from standard curve runs (B). Left lower panel: variation of F _max , Y _f . and m versus increasing inhibitor concentration. The variation is expressed as Relative Error = ; where is the mean of parameter calculated for each inhibitor concentration; represents the mean of parameter value from standard curve samples (C). Right lower panel: asymmetry values versus increasing inhibitor concentration. Asymmetry was computed as the following ratio: (D).