A High Density Component in Several Vertebrate Enteroviruses

Abstract

SUMMARYIn addition to the major infective component, which bands at a density of 1"34 g/ml in caesium chloride ('light component'), a component with a density of 1"44 g/ml ('heavy component') has been found in harvests of poliovirus (type I), Coxsackie B5 virus, a bovine enterovirus ) and swine vesicular disease virus (SVDV). With SVDV about 98 % of the infectivity equilibrated at 1.34 g/ml but approx. 2 ~oo was present as a peak at t.44 g/ml. The morphology of the two forms was similar but the heavy component had a smaller diameter (28 nm) than the light component (30 nm). No inter-conversion of the two forms was observed on re-cycling in fresh caesium chloride gradients and the two components had the same proportions of RNA and protein and the same polypeptide composition. Each component gave a similar proportion of the light and heavy forms on replication, but the light component had a specific infectivity about fourfold higher than that of the heavy component and was also much more efficient in eliciting the formation of neutralizing antibodies in guinea pigs. Although these results suggest that the two particles are alternative stable configurations of the virus, iodination failed to reveal any differences in the extent or pattern of labelling of the polypeptides in the two forms.

Echovirus 11 Dense Particles: Isolation and Preliminary Characterization

“…The specific infectivity of dense particles was 120 times lower than that of standard particles. This was in agreement with data obtained for other picornavirus dense particles which were also less infective than standard particles (Rowlands et al, 1975;Yamaguchi-Koll et aL, 1975). Electron microscopic examination using 1% sodium silicotungstate negative staining of virus suspended in PBS pH 7.2 showed similar features of dense and standard particles which appeared as compact, sphere-like particles (Fig.…”

“…The average diameter of dense particles (25.28 _+ 0.77 nm) was slightly less than that of standard particles (28.10 + 0.75 nm). Similar differences in size of standard and dense particles were reported for SVDV (Rowlands et al, 1975). Haemagglutinating activity was tested by microtitre method using a 0.6% suspension of human O + erythrocytes (Cova & Aymard, 1980).…”

“…particles of higher buoyant density (density 1-44 g/ml) in CsC1 than standard particles (density 1.33 g/ml), have been described for several picornaviruses: poliovirus, coxsackie B5 virus, mengovirus, bovine enterovirus, and swine vesicular disease virus (SVDV) (Rowlands et at., 1975;Yamaguchi-Koll et al, 1975;Wiegers et al, 1977;Perez-Bercoff et al, 1978). Antigenic properties and chemical properties, such as amount of RNA, polypeptide composition, and RNA to protein ratio, are similar for dense and standard particles.…”

“…Antigenic properties and chemical properties, such as amount of RNA, polypeptide composition, and RNA to protein ratio, are similar for dense and standard particles. It was suggested (Rowlands et al, 1975;Perez-Bercoff et al, 1978) that higher buoyant density results from conformational differences between dense and standard particles, dense particles having a more open capsid structure leading to a greater interaction of virus RNA with Cs + ions (Rowlands et al, 1975;Yamaguchi-Koll et al, 1975;Wiegers et aL, 1977Wiegers et aL, , 1978Mapoles et al, 1978).…”

Characterization of a New Picorna-like Virus Isolated from Aphids

“…These characteristics together with its serological relationship to CrPV, an insect picornavirus (Matthews, 1982), justify the classification of ALPV in the family Picornaviridae. In addition, virion preparations contain particles of high density, similar to the dense components observed for Drosophila C virus (Jousset et al, 1977), poliovirus (YamaguchiKoll et al, 1975) and several other enteroviruses of vertebrates (Rowlands et al, 1975).…”