Virus-like particles in yeast: isolation and infectivity.

Virus-like particles containing electron dense cores are seen in thin sections of intact and degenerated cells of a thermosensitive (ts) strain of Candida tropicalis. A particulate fraction not present in wild-type cells has been isolated from the ts cells disrupted by pressure. The particles are 80-120 nm in diameter. Empty particles with a central cavity are observed. The method of infecting mating pairs of Saccharomyces cerevisiae by partially purified particles is described.