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Biomedical subjects

N Biswal

Publications and source records attributed to N Biswal.

At least 37 records · Page 2Linked to original sources

The fate of parental herpesvirus DNA after infection with normal and photoinactivated virions.

The fate of the 3H-dT-labelled parental DNA of normal and photoinactivated herpes simplex virus type 1 (KOS strain) was followed for 8 h after infection. The sedimentation coefficients of parental virus DNA from cells infected with normal virons increased and became associated with the replicative intermediates of HSV-1 DNA. When cultured in 5-bromodeoxyuridine-containing medium, the buoyant density of the normal parental virus DNA shifted to the hybrid region (containing heavy and light molecules) of the caesium chloride density gradient. The parental virus DNA of photoinactivated virions, however, degraded quickly and did not participate in progeny virus DNA replication.

Centrifugation, Density Gradient↗

Photodynamic treatment of herpes simplex virus during its replicative cycle.

Photodynamic treatment of herpes simplex virus type 1-infected hamster embryo fibroblasts (LSH strain) with a low concentration of proflavine (0.08 mug/10(5) cells per ml), a 3-9-diamine acridine dye, inhibited production not only of infectious progeny but also of virion particles. However, there was no appreciable inhibition of viral or cellular DNA synthesis, even when the infected cells were repeatedly exposed to this low concentration of dye and light during the replication cycle of the virus. It thus appears that photodynamic treatment of infected cells interferes with the processes involved in virus maturation.

Culture Techniques↗

Cyclic appearance of defective interfering particles of herpes simplex virus and the concomitant accumulation of early polypeptide VP175.

Serial passage of undiluted herpes simplex virus types 1 and 2 resulted in cyclic production of infectious and defective virions. Defective virus production was characterized by the appearance of a new species of viral DNA with a higher bouyant density in CsCl than standard viral DNA. Measurement of the infectivity titer and DNA synthesis revealed that the defective particles interfered with the replication of standard virions and stimulated the overproduction of a large molecular weight (175,000 daltons) polypeptide.

Cell Line↗

Modified radioimmunoassay for murine sarcoma-leukemia virus group-specific antigen.

Iodination of disrupted Moloney strain murine sarcoma-leukemia virus resulted in labeled group-specific (gs) protein which was subsequently purified on an isoelectrofocusing column. This iodinated purified gs antigen, prepared from a relatively small quantity of purified virus, was used in a radioimmunoassay. A radioimmunoassay inhibition method was developed so that antibody specific for mammalian C-type gs antigen could be measured in undiluted or low dilutions of test serum without altering the known reagents of the test. The gs antigen isolated from purified Moloney strain murine sarcoma-leukemia virus has an isoelectric point (pH 5.95) which is significantly lower than that reported for other murine leukemia viruses.

Antibodies, Viral↗

Polymerase activity of Pichinde virus.

Pichinde virus, a member of the arenavirus group, was examined for polymerase activity. Purified virus was found to contain RNA-dependent RNA polymerase but not RNA-dependent DNA polymerase activity. Since RNase but neither DNase nor actinomycin D inhibited the endogenous polymerase reaction, RNA of the virus appeared to be used as the template. The divalent cations Mg(2+) and Mn(2+) were required for optimal reactivity. The RNA product was partially resistant to RNase and the resistant portion had a sedimentation coefficient of 22 to 26S in sucrose gradients.

Animals↗

Replication of the Moloney murine sarcoma-leukemia virus in XC cells.

The XC rat cell line was found to support the replication of a strain of the Moloney murine sarcoma-leukemia virus. In growth curve experiments cytopathology was paralleled by the production of murine sarcoma virus and leukemia virus progeny having the biologic, antigenic, and biophysical properties of the infecting virus.

Animals↗

Characterization of nucleic acid of pichinde virus.

The nucleic acid of Pichinde virus was found to be single-stranded ribonucleic acid (RNA) as determined by sensitivity to ribonuclease, by alkaline degradation, by buoyant density in cesium sulfate, and by analysis of the base composition. The RNA of the virion could be separated into five components which had sedimentation coefficients corresponding to 31S, 28S, 22S, 18S and 4 to 6S. The 28S, 18S, and possibly the 4 to 6S RNAs appear to be derived from host cell components incorporated into the virion, whereas the 31S and 22S components appear to represent the genome of the virus.

Animals↗