Isolation and characterization of a virus from the intracellular green alga symbiotic with Hydra viridis.

The isolation and characterization of a virus (designated HVCV) from the symbiotic Chlorella-like green alga present in Hydra viridis (Florida strain) are described. The large polyhedral viral particle sedimented at ca. 2600 S in sucrose density gradients and had a buoyant density in CsCl of 1.295 g/ml. The virus contained at least 19 polypeptides (MW range, 10,300 to 82,000) and the major polypeptide (MW, 46,000) was a glycoprotein. The viral genome consisted of a double-stranded DNA with a buoyant density in CsCl of 1.7114 g/ml (52% GC) and a molecular weight of ca. 136 x 10(6).