Selection of a suitable viral DNA extraction method for Sheeppox virus in cell culture

A suitable method for the extraction of nucleic acids should be efficient, sensitive, rapid and simple. Moreover, ideally, good method should yield pure nucleic acid-free from any contaminant inhibitors. Several methods have been reported for viral deoxyribonucleic acid (DNA) isolation but limited information is available on quick and simple isolation of Sheeppox virus (SPPV) genomic DNA in cell culture. In this study, the healthy Vero cells and primary lamb testis cells were infected with SPPV strains such as SPPV-Jaipur, SPPV-Ranipet and SPPV-Roumanian Fanar (RF) and harvested when it exhibited clear cytopathic effect (CPE) in culture. Four different DNA extraction methods i.e., (i) Phenol/chloroform/Isoamyl alcohol method, (ii) Cell lysis buffer method, (iii) Proteinase-k method, and (iv) commercial nucleic acid extraction kit was used to extract optimum yield of viral genomic DNA from clarified culture supernatant of harvested SPPV virus. The DNA sample was characterized using the Nanodrop spectrophotometer and agarose gel electrophoresis. Significantly (p<0.05) higher yield of SPPV genomic DNA was obtained in proteinase-k method which was about 3-5 times more than other methods. Among these methods, proteinase-k protocol was found to be comparatively very effective method in terms of yield of viral genomic DNA, and was free from PCR inhibitors.