Some biophysical properties of frog viruses and their DNA.

Abstract
The progeny of two viruses, FV1 and FV3 isolated from normal and tumor-bearing frogs, respectively, and grown in chick embryo cells at room temperature were found to be heterogeneous with respect to buoyant density in CsCl solution. The bulk of virions characterized by an average buoyant density of 1.305 gm/em3 in CsCl is noninfectious. A small fraction with a buoyant density of 1.287 gm/cm3 is infectious. FV1 and FV3 contain DNA with a buoyant density of 1.720 gm/cm,3 i.e., higher than that of chick embryo DNA. The relationship between the viruses Isolated from frogs and herpes viruses is discussed.