RESUMO
Objective To establish a fluorescence quantitative PCR assay for polyomavirus and to apply this technique in the investigation of its infection rate in naked mole rats. Methods To compare the nucleic acid sequence of murine polyomavirus (Genbank:NC 001515) in NCBI and design primers and probes in its conserved region. To establish a fluorescence quantitavive PCR method for polyomavirus and evaluate the sensitivity and specificity of the method. To infect nine one-day old KM strain suckling mice, and to collect samples of the heart, liver, spleen, lung, kidney, brain, thymus, cecal contents and blood at 21 days after infection. The efficacy of the method was validated by detecting the virus in organs. 62 cecal samples from naked mole rats were tested by the established assay. Results There was obvious fluorescence signal when polyomavirus was used as the template and no fluorescence signal when simian virus 40, murine K virus, MVM and H-1 were used as templates. The detection limit of the assay was 100 copies/μL. Polyomavirus DNA was detected in the heart, liver, spleen, lung, kidney and cecal contents of the mice which were inoculated with polyomavirus. The polyomavirus DNA content was highest in the lung tissue. There was no detectable polyomavirus DNA in the brain, thymus and blood of the infected mice. Sixty-two cecal contents of naked mole rats were tested for polyomavirus and the results were negative. Conclusions The fluorescence quantitative PCR assay for polyomavirus established in this study can effectively detect polyomavirus DNA in animal tissues. The results of investigation of the natural infected polyomavirus of naked mole rats provide a reference for the formulation of microbiological criteria for experimental naked mole rats.
RESUMO
Objective To establish a dual RT-PCR detection method for bovine viral diarrhea virus(BVDV)in bovine-derived samples. Methods The primers were designed and synthesized according to the published BVDV1 and BVDV2 genes containing highly conservative sequences in the 5' untranslated regions(5' UTR)to establish the dual RT-PCR method. The specificity,sensitivity,stability of this method were evaluated. Then 41 bovine-derived samples and 64 bovine plasma samples including bovine calf serum, deproteinized calf serum extract and one lienal polypeptide injection were detected with this method. Results There was no cross reaction with bovine parainfluenza virus type 3(BPIV3), classical swine fever virus(CSFV)and Japanese encephalitis virus(JEV)when samples were detected with the established dual RT-PCR method. The lowest concentration of template DNA for detection of BVDV1 and BVDV2 was 8.87 × 102copies and 6.31 × 102copies per microliter,respectively. Electrophoresis bands of about 151 bp and 303 bp were still amplified and detected after the BVDV1 and BVDV2 cDNA was stored at -30℃ for 12 months. The BVDV positive rate of 41 bovine-derived samples and 64 bovine plasma samples detected with this dual RT-PCR method was 14.6% and 29.7%, respectively. Conclusions The established dual RT-PCR method has the advantages of high efficiency, specificity,sensitivity and stability,and can be used for the detection of BVDV in bovine-derived samples.