[Characterization of RNA polymerase activity of highly purified preparations of influenza virus A/duck/Alberta/48/76].

The influenza virus A/duck/Alberta/48/76 with the antigen formula H7N3 (16) and Hav1 Nav2 (WHO nomenclature from 1971) (15), respectively, as well as a nonpathogenic virus of the subtype Hav1 were purified to a high degree by ultracentrifugation in continuous sucrose gradients (15-40% w/w and 20-60% w/w, respectively). The activity of the RNA polymerase of this virus preparation was determined by incorporating 3H-UMP in acid insoluble material following preincubation of the virus with the nonionic detergens Nonidet P-40 for 15 min at 32 degrees C. The influence of different concentrations was investigated of dinucleotid, NaCl, MgCl2, Nonidet P-40 and different incubation temperatures. Optimal incorporation rates were found at following conditions: 0.2 mM dinucleotid ApG, 150 mM sodium chloride and 8 mM magnesium chloride by concentration of ions, 0.25-0.5% detergens Nonidet P-40 as well as a temperature of incubation of 32 degrees C. The data for optimal polymerase activity for the avian influenza virus A/duck/Alberta/48/76 are generally not different from the conditions described for the Fowl-Plague-Virus and for human strains.