Characteristics of feline panleucopaenia virus strains enabling definitive classification as parvoviruses

Summary

The viruses causing feline panleucopaenia and mink enteritis are shown to have the morphology of parvoviruses, with a mean diameter between 21 and 24 nm. Buoyant density studies show that purified virus of both strains consists of particles which band as “complete” virus at a main density of 1.41 g/ml, with a minor population at a density of 1.44 g/ml. Other particle species with a lower content of DNA, or no detectable DNA, occurred at mean buoyant densities of 1.36 and 1.31 g/ml, respectively.

For both feline panleucopaenia and mink enteritis viruses, sedimentation coefficients of DNA from the three density levels which contain DNA, gave results conforming to those expected for single stranded DNA, whilst buoyant density studies showed the DNA of all three species to have a mean density of 1.722. The calculated molecular weight of the DNA of particles banding at 1.41 g/ml (1.7×10⁶ daltons) represents 28.5 per cent of the total particle weight (5.9×10⁶ daltons).

Viral protein can be separated into two major polypeptides with molecular weights of 60,300 and 73,100, amounting to 86 and about 10 per cent, respectively, of the total radioactive amino acids incorporated. A third minor component of molecular weight 39,600 daltons was present at concentrations between 3 and 6 per cent.