Abstract
Aspergillus foetidus virus S (AfV-S) and A. foetidus virus F (AfV-F) have been shown to be serogically unrelated. Amino acid compositions of the two virus capsids are compared and their capsid polypeptides have been examined by SDS-polyacrylamide gel electrophoresis. AfV-F contained one major (3) and two minor (1 and 2) polypeptides with mol. wt. 87000, 125000 and 100000, while AfV-S contained one major (σ1) and one minor (σ2) polypeptide with mol. wt. 83000 and 78000 respectively. Evidence is presented that σ2 may be derived from σ1 polypeptide by proteolytic degradation in vitro. The mol. wt. of AfV-F4 and AfV-S1a particles were found from sedimentation and diffusion coefficients to be 13.1 x 106 and 12.4 x 106 respectively. AfV-F capsid was estimated to contain 120 molecules of polypeptide 3 and one molecule each of polypeptides 1 and 2, while AfV-S capsid was estimated to contain 120 molecules of polypeptide 1.
It has been shown that S1a and S2a particles each contain a molecule of double-stranded RNA with mol. wt. 2.24 x 106 (RNA-224) and 2.76 x 106 (RNA-276) respectively, whereas S1b and S2b particles each contain a molecule of RNA-224 and RNA-276 respectively, together with an additional molecule of double-stranded RNA of mol. wt. 0.1 x 106. Evidence is presented that S4 particles contain two molecules of RNA-224. S3 particles gave only RNA-224 on extraction, but contain the equivalent of 1 molecules of RNA-224; the nature of these particles and other possible virus replicative intermediates is discussed. Double-stranded RNA of mol. wt. 1.24 x 106 was derived from a newly described particle class, Fo.