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U.S. Department of Energy
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Polyamine biosynthesis and the replication of turnip yellow mosaic virus

Thesis/Dissertation ·
OSTI ID:6103499
Turnip yellow mosaic virus (TYMV) contains large amounts of nonexchangeable spermidine and induces an accumulation of spermidine in infected Chinese cabbage. By seven days after inoculation, a majority of protoplasts isolated from newly-emerging leaves stain with fluorescent antibody to the virus. These protoplasts contain 1-2 x 10/sup 6/ virions per cell and continue to produce virus in culture for at least 48 hours. (/sup 14/C)-Spermidine (10 ..mu..M) was taken up by these cells in amounts comparable to the original endogenous pool within 24 hours. However, the spermidine content of the cell was only marginally affected, implying considerable regulation of the endogenous pool(s). Putrescine and spermine were major products of the metabolism of exogenous spermidine. Radioactivity from exogenous (/sup 14/C)-spermidine was also readily incorporated into the nucleic acid-containing component of the virus, where it appeared as both spermidine and spermine. Thus, newly-formed virions contained predominantly newly-synthesized spermidine and spermine. However, inhibition of spermidine synthesis by dicyclohexylamine (DCHA) led to incorporation of pre-existing spermidine and increased amounts of spermine into newly-formed virions. The latter results were tested and confirmed in a second cellular system, consisting of health protoplasts infected with TYMC in vitro.
Research Organization:
State Univ. of New York, Stony Brook (USA)
OSTI ID:
6103499
Country of Publication:
United States
Language:
English