Rapid Detection of PCV2 Based on Double Molecular Beacons

A double-molecular beacon based assay (DMB) was developed for the determination of porcine circovirus 2 (PCV2). Two kinds of single-stranded DNA molecular beacons, which could specifically hybridize with PCV2 genome DNA, were designed according to the characteristics of PCV2 genome sequences. The fluorescence signal of DMB was enlarged about 80 times, which was 2–4 times higher than that of single molecular beacon. Under the optimum conditions of 10 mM MgCl2 and 20 mM Tris-HCl (pH 8.0), the fluorescence signal of DMB was increased linearly with the target DNA concentration ranging from 2 nM to 200 nM with a detection limit of 1 nM. The method was applied to detect PCV2 in the genomes of 18 swine fever samples. The results showed that 8 cases were PCV2 positive, which were further confirmed by PCR.

DMB detection system consisted of two special molecular beacons MB1 and MB2, those could completely hybridize with the two conserved regions of PCV2 genome. When MB1, MB2 and PCV2 genome co-incubate, the molecular beacons could hybridize with PCV2, causing fluorescent emission. The variation of fluorescence intensity reflected the concentration of PCV2 genome.Figure optionsDownload as PowerPoint slide