The isolation of cytoplasmic polyhedrosis virus from the white-marked tussock moth, Orgyia leucostigma (Smith)

The procedure for isolating and purifying free and occluded cytoplasmic polyhedrosis virions was improved. The virions are resistant to the enzymes RNase, DNase, trypsin, chymotrypsin, and phospholipase C, and to a detergent, deoxycholate. The use of these enzymes and deoxycholate, in combination with discontinuous and linear sucrose gradients, produced very pure preparations of free virions. Occluded virions were released by dissolving polyhedra in 0.05 M Na 2 CO 3 – 0.04 M NaCl for 60 min at room temperature. The composition of the virion was estimated to be about 28% RNA and 72%protein.