title: Viruses of Entamoeba histolytica. 3. Properties of the polyhedral virus of the HB-301 strain.
abstract: Some biological characteristics and bioassay of a polyhedral virus isolated from normal-appearing strain HB-301 of Entamoeba histolytica are described. The virus produced lysis of susceptible strains of E. histolytica, yet it caused no cytopathological effect in the host strain, HB-301. The virus and host amoeba existed in an equilibrium; approximately 10(4) mean infective dose units of virus were produced per million HB-301 amoebae. Superinfection and antiviral antiserum treatment failed to disturb this equilibrium permanently. The mechanism of viral persistence in strain HB-301 amoebae remains to be determined. Purification of the virus was attempted. Ninety-nine percent of the viral infectivity was associated with a low-speed pellet which consisted of complexes of virus and cellular membranes. Various treatments of this low-speed pellet failed to release virus. Biologically active, membrane-free virus of low titer was prepared by differential centrifugation of supernatant solutions and employed in electron microscopy and other studies.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000382:microbiology; D002499:Centrifugation, Density Gradient; D004748:Entamoeba histolytica / Q000166:cytology / Q000254:growth & development; D005260:Female; D005615:Freezing; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera; D007181:Inclusion Bodies, Viral; D008851:Micropore Filters; D008854:Microscopy, Electron; D009500:Neutralization Tests; D009995:Osmosis; D011817:Rabbits / Q000276:immunology; D014461:Ultracentrifugation; D014779:Virus Replication; D014780:Viruses / Q000187:drug effects / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification
chemical_list: D007106:Immune Sera