ABSTRACT
A double-molecular beacons (DMB) based assay was developed for porcine circovirus 2(PCV2) detection. Two single-stranded DNA molecular beacons which could specifically hybridize with PCV2 genome DNA respectively in different sequence were designed according to the characteristics of the PCV2 genome sequences. The fluorescence signal was amplified 80 times by DMB, which was 2-4 times higher than that of single molecular beacon. Under the optimal conditions of 10 mmol/L MgCl2 , 20 mmol/L Tris-HCl (pH=8. 0), 40 ℃ and 30 min incubation time of DNA with DMB, the enlargement factor was increased linearly with DNA concentration over the range from 2 nmol/L to 200 nmol/L, with a detection limit of 1 nmol/L. The method was applied to detect PCV2 in genome of 18 swine fever samples and 8 PCV2 positive cases were found, which were confirmed by PCR method.