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D G Sharp

Publications and source records attributed to D G Sharp.

At least 37 records · Page 2Linked to original sources
PubMed1970

Spectrum of physical properties among the virions of a whole population of vaccinia virus particles.

Populations of virions released from cultures of L cells infected with vaccinia virus are composed of particles which differ substantially from each other in sedimentation rate and buoyant density. Clumps of two and three virions sediment enough faster than single particles so that fractions containing only singles and others with predominantly pairs can be isolated. The observed velocity range for single particles is much greater than that attributable to diffusion and convection in the centrifuge. Plaquing efficiency is three times higher in a small fraction of the slowest-moving virions than in the major part of the population, even though no size difference can be seen in the electron microscope. Isopycnic densities in potassium tartrate range from 1.15 to 1.23, enough to account for the observed range in velocities. Centrifugation was done in the BXIV zonal rotor at very low virion concentration (less than 10(8) per ml at any point in the spectrum). Virus count and state of aggregation were determined by electron microscopy.

Centrifugation, Density Gradient↗
PubMed1967

Multiplicity reactivation of vaccinia virus particles treated with nitrogen mustard.

The nitrogen mustard bis(beta-chloroethyl)methylamine, a radiomimetic alkylating agent, is known for its ability to inactivate viruses in general and poxvirus in particular. These experiments show that vaccinia virus is rapidly inactivated by it. They show, in addition, that the treated virus exhibits multiplicity reactivation in L cells, closely resembling that experienced with the same virus after exposure to ultraviolet rays. These findings have come from observations of plaque titer, on the one hand, and virus particle aggregation (measured in the electron microscope), on the other. The titer of the treated virus is very sensitive to particle aggregation, increasing and decreasing in a reversible manner as the degree of clumping among the particles is changed. The magnitude of these changes is such that they must be considered in any situation involving plaque assay of the fraction of virus surviving treatment with nitrogen mustard.

Centrifugation↗