Biophysical Studies of Vesicular Stomatitis Virus

Abstract

The infectivity and morphology of vesicular stomatitis virus (VSV) were studied after density gradient centrifugation in cesium chloride (CsCI), potassium tartrate (KT), and sucrose. Centrifugation in CsCl revealed two equally infectious bands corresponding to densities of 1.19 and 1.22 g/ml, and a third (density, 1.26 g/ml) band of low infectivity. Two bands (densities of 1.16 and 1.18 g/ml) were observed in the KT gradient, in which the lighter band contained most of the infectivity. Centrifugation in sucrose resulted in a single broad infectious band (density, 1.16 g/ml). The typical rodshaped VSV particles were found mainly in the lighter bands obtained in CsCl (1.19 g/ml) and KT (1.16 g/ml) and in the single sucrose gradient band (1.16 g/ml). Bent particles equally as infectious as the rod-shaped particles were a constant finding in the CsCl preparations, and were observed mainly in the second band (density, 1.19 g). Numerous strands 15 m,u wide were found in the third CsCl (density, 1.26 g/ml) and the second KT (1.18 g/ml) bands. Similar strands could be liberated from VSV particles after treatment with deoxycholate. Internal transverse striations were found to be a regular feature of VSV particles examined with the pseudoreplication negative-staining technique. For crude virus stocks, the physical particle-toinfectivity ratio ranged from 73 to 194. Several morphological similarities between VSV and myxoviruses were observed, including 10 m, surface projections, pleomorphic morphological forms, and 15 mMi seemingly nucleoprotein strands.

Analysis of virion associated host proteins in vesicular stomatitis virus using a proteomics approach

“…In addition to standard "bullet shaped" particles, there were also large numbers of "bent" particles where the virion appears to have been broken in half. These bent particles have been shown to be a substantial component of at least some VSV preparations and are infectious [31]. The presence of other "irregular" particles is consistent with previous studies demonstrating that VSV virions can easily undergo morphological changes…”

“…when most cells were infected but significant cell detachment had not yet occurred (to maximize exclusion of cellular debris), and virions were purified using a discontinuous sucrose gradient purification protocol as described in the Materials and methods section. Initial concentration of virus by polyethylene glycol precipitation [30] as well as the use of continuous sucrose [30], cesium chloride [31], and iodixanol gradients [32] were also tried without significant improvement in sample infectivity or purity (data not shown).…”

Cellular Proteins Associated with the Interior and Exterior of Vesicular Stomatitis Virus Virions

“…The purity of the resulting material was then examined by electron microscopy (EM). As seen in Figure 1, nearly all of the material present was clearly identifiable as VSV virions, although many of them were bent, a previously observed form that is generally believed to be infectious [57] and may represent an EM processing artifact [58,59]. The titer of these purified virions on BHK-21 cells was 1.4610 11 PFU/ml, demonstrating this preparation was highly infectious.…”

Chronic non-A, non-B hepatitis: Ultrastructural and serologic studies

“…The convalescent serum did not react by CIEP with purified HBsAg, with sera from individuals with no history of liver disease, or with extracts of normal human liver. Sera obtained on the day of biopsy were examined for the presence of virus-like particles by electron microscopy using a pseudoreplication technique (19). Numerous spherical particles ranging in diameter from 14 to 37 nm were observed in the sera of the five patients.…”