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Biomedical subjects

D Baltimore

Publications and source records attributed to D Baltimore.

At least 505 records · Page 28Linked to original sources
PubMed1971

Defective interfering particles of poliovirus. I. Isolation and physical properties.

A class of defective interfering (DI) poliovirus particles has been identified. The first was found as a contaminant of a viral stock; others have been isolated by serial passage at a high multiplicity of infection. The DI particles are less dense than standard virus and sediment more slowly. Their ribonucleic acid (RNA) sediments more slowly than standard RNA and has a higher electrophoretic mobility. Competition hybridization experiments with double-stranded viral RNA indicate that DI RNA is 80 to 90% of the length of standard RNA. The proteins of DI particles are indistinguishable from those of standard poliovirus.

Carbon Isotopes↗
PubMed1971

Effect of pactamycin on synthesis of poliovirus proteins: a method for genetic mapping.

We have studied the effect of the drug pactamycin on protein synthesis in poliovirus-infected HeLa cells. At a concentration which primarily inhibits initiation of protein synthesis, the spectrum of poliovirus proteins synthesized is markedly changed. The amount of NCVP 1, the capsid precursor, is greatly reduced relative to NCVP 2 and the amount of NCVP X is slightly reduced. Since it is believed that there is only one major site for the initiation of protein synthesis on the poliovirus genome, we interpret this differential effect on the poliovirus proteins to be an indication of their relative distance from the initiation site. On this basis, we propose a gene order for the poliovirus genome (5' --> 3') of NCVP 1, NCVP X, NCVP 2.

Antibiotics, Antineoplastic↗
PubMed1969

Ribonucleic acid synthesis of vesicular stomatitis virus. I. Species of ribonucleic acid found in Chinese hamster ovary cells infected with plaque-forming and defective particles.

Plaque-forming B particles of vesicular stomatitis virus (VSV) induce the synthesis of virus-specific ribonucleic acid (RNA) in Chinese hamster ovary cells, whereas defective T particles do not. Infection with low input multiplicities of B results in the formation of four species of RNA. During infection with high multiplicities, RNA synthesis begins with mainly these four species of RNA but gradually shifts to a new pattern of RNA synthesis involving five other species of RNA. The change can also be induced by superinfection with T at 2.5 hr after infection with a low multiplicity of B. T added at the same time as B prevents virtually all RNA synthesis. Synthesis of the first group of RNA species correlates with the formation of B particles, whereas synthesis of the second group correlates with the formation of T particles. The various species of RNA formed after infection with VSV particles include single-stranded RNA, a completely double-stranded RNA, and RNA with partially double-stranded regions. These observations begin to establish a molecular basis for understanding the ability of T particles to interfere with the growth of B particles.

Animals↗
PubMed1968

Isopycnic separation of subcellular components from poliovirus-infected and normal HeLa cells.

A rapid method for determining the density of ribonucleoprotein particles and complexes has been developed. The method involves glutaraldehyde fixation of sucrose gradient fractions and immediate centrifugation for 5 hours through preformed cesium chloride gradients. There is little or no aggregation of particles, so that components which co-sediment in sucrose gradients are resolved by the cesium chloride gradient. By this method the densities of HeLa cell ribosomes, polyribosomes, and subribosomal particles have been determined. Furthermore, the poliovirus replication complex has been separated from polyribosomes and its density has been found to be unaffected by treatment with ethylene-diaminetetraacetic acid.

Aldehydes↗