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Isolation and characteristics of the DNA from nuclear polyhedrosis virus

ScholarsArchive at Oregon State University

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Title Isolation and characteristics of the DNA from nuclear polyhedrosis virus
Names Carnegie, John William (creator)
Beaudreau, George S. (advisor)
Date Issued 1969-12-18 (iso8601)
Note Graduation date: 1970
Abstract The genome of the nuclear polyhedrosis virus which infects the
larvae of the tussock moth, the lepidopteran, Hemerocampa
pseudotsugata, was isolated, identified as deoxyribonucleic acid, and
characterized in terms of its physical and biological properties. An
isolation procedure for the viral DNA was established which consisted
of the following steps: the polyhedra were isolated by isopycnic
centrifugation in a sucrose density gradient; the virus bundles
were released from the polyhedra by solubilization of the polyhedron
protein at pH 11.6 and concentrated by centrifugation; the virus
bundles were disrupted by sodium dodecyl sulfate treatment to release
the viral DNA genome; the viral DNA from the virus bundle
lysate was banded in a cesium chloride density gradient; and the
viral DNA fraction was recovered in a relatively pure state and
dialyzed against buffer.
The isolated viral genome was identified as DNA by its susceptibility
to deoxyribonuclease, its buoyant density in cesium chloride,
its ultraviolet absorption spectrum, and its melting curve. The viral
DNA was found to have a buoyant density in cesium chloride of 1.710
gm/ml, a melting temperature of 92°C, and a guanine + cytosine
base composition of 47 molar percent. The viral DNA genome was
shown to exist, at times, as a circular molecule by ethidium bromidecesium
chloride density gradient analysis. The molecular weight of
the molecule was found to be 96 x 10⁶ daltons by velocity sedimentation
analysis. The isolated viral DNA genome was shown to cause
about 60% lethal polyhedrosis when injected into H. pseudotsugata
larvae at a concentration of 25 mμg of DNA per larva.
The nuclear polyhedrosis virus of H. pseudotsugata was compared
to other insect viruses and to other major groups of animal
and bacterial deoxyriboviruses on the basis of the properties of the
viral DNA. The nuclear polyhedrosis virus of H. pseudotsugata
fits easily into the group of insect polyhedrosis viruses, but the
polyhedrosis viruses, as a group, must be considered separately
from other deoxyriboviruses. The nuclear polyhedrosis viruses have
several features which make them a desirable model with which to
study DNA replication, transcription, translation and other virus-host
relationships.
Genre Thesis/Dissertation
Topic DNA
Identifier http://hdl.handle.net/1957/46174

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