Characterization of a mycoplasma virus (MV-O1) derived from and infecting Acholeplasma oculi

A new Mycoplasmatales virus, referred to as MV-O1, was isolated during cloning of Acholeplasma oculi 19L. The virus formed plaques only on strains of A. oculi, i.e. the original clone, A. oculi 19L, a subclone of A. oculi 19L (A.oculi-i), A. oculi Goat 5 and wild isolate (K-2) of A. oculi, but not on other acholeplasmas, including strains of A. laidlawii, nor on five human mycoplasma species tested. The virus required horse serum for multiplication as well as for plaque formation and passed through a 100 nm filter. Electron microscopy revealed enveloped, spherical particles 80-130 nm in diameter. The buoyant density of purified virus was 1.23 g ml-1 in CsCl, and agarose gel electrophoresis indicated that the viral nucleic acid was DNA.