HIS1, AN ARCHAEAL VIRUS OF THE FUSELLOVIRIDAE FAMILY THAT INFECTS HALOARCULA-HISPANICA

A novel archaeal virus, His1, was isolated from hypersaline waters in southeastern Australia. It was lytic, grew only on Haloarcula hispanic a (titers of up to 10(11) PFU/ml), and displayed a lemon-shaped morpho logy (74 by 44 nm) previously reported only for a virus of the extreme thermophiles (SSV1). The density of His1 was approximately 1.28 g/ml. similar to that of SSV1 (1.24 g/ml). Purified particles were resistan t to low salt concentrations. The genome was linear, double-stranded D NA of 14.9 kb, similar to the genome of SSV1 (15.5 kb), Morphologicall y, this isolate clearly belongs to the recently proposed Fusellovirida e family of archaeal viruses. It is the first member of this family fr om the extremely halophilic archaea, and its host, H. hispanica, can b e readily manipulated genetically.