The proposed work will be directed toward the general objective of characterizing the biology of the mycoplasmaviruses. MVL2 DNA replicative intermediates will be analyzed in normal infected and persistently infected cells. Acridine dye stimulation of MVL51 virus yield will be studied, to investigate which polymerases are involved in viral replication. MVL2 virus membrane-cell membrane interactions will be examined. The details of MVL3 infection will be studied in terms of the nonlytic cytocidal nature of viral assembly and release.