Altered molecular species of human interferon produced in the presence of inhibitors of glycosylation

The inhibitors of glycosylation, 2-deoxy-D-glucose or D-glucosamine, inhibit the synthesis of biologically active interferon in human FS-4 fibroblast cultures stimulated with polyinosinate-polycytidylate. Interferon synthesized in the presence of partially inhibitory concentrations of 2-deoxy-D-glucose or D-glucosamine were found to differ from interferons made in control cultures in some physical properties. Interferons synthesized in the presence of either inhibitor had a diminished charge heterogeneity demonstrable by iso-electric focusing. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, control interferon activity formed a single peak with the apparent molecular weight of 20,000, whereas interferons from cultures treated with either inhibitor could be resolved into two distinct molecular weight components, one of which was smaller than the interferon synthesized in control cultures.

Hepatocellular carcinoma and chronic persistent hepatitis

The morphologic type of cirrhosis that is followed most frequently by hepatocellular carcinoma is posthepatitic cirrhosis. Furthermore, HB AG is detected in a high rate among cases with hepatocellular carcinoma suggesting the intimate causal relationship between hepatitis b virus and hepatocellular carcinoma. It has been considered that hepatocellular carcinoma might develop during destruction and regeneration of fully developed liver cirrhosis. However, hepatocellular carcinoma is combined with not only liver cirrhosis but also with mild liver fibrosis. An attempt was made to determine HBs Ag in the liver tissue of liver fibrosis with hepatocellular carcinoma. HBs Ag was found in non-cancerous liver tissue of 40 percent of those cases. Therefore, it may be concluded that, at least some of those fibrosis is caused by chronic viral hepatitis and hepatocellular carcinoma may develop not only on posthepatitic cirrhosis but also on chronic persistent hepatitis. This evidence also suggests the carcinogenicity of hepatitis B virus.

Purification and biophysical properties of acute haemorrhagic conjunctivitis virus

The buoyant density of acute haemorrhagic conjunctivitis virions labeled with either [(3)H]uridine or [(3)H]leucine was 1.34 g/ml in CsCl and 1.25 g/ml in sucrose. RNA extracted from the virions gave a sedimentation coefficient of approximately 34S in sucrose, and was found to be sensitive to RNase. Molecular weight of RNA was calculated to be 2.5 x 10(6) using poliovirus RNA for reference.

Gamma ray-induced small plaque mutants of western equine encephalitis virus

Small plaque mutants of Western equine encephalitis virus were obtained from the surviving fractions of wild-type virus which was irradiated with gamma rays. The frequency with which small plaque mutants appeared in the surviving fraction increased with the radiation dose. These mutants were not more resistant to radiation than wild-type virus. The growth rate of a mutant, S127, was lower than that of wild-type. Clonally purified mutant virions presented two peaks in a velocity sedimentation profile; peak 1 corresponded to the peak of wild type and peak 2 moved faster than peak 1. Virions of both peaks were infectious and consistently formed small plaques in chicken embryo cells. Virions reisolated from either peak and grown in chicken embryo cells also revealed two peaks in sedimentation analysis. In the electron microscope examination peak 2 proved to consist of giant form particles, each of which contained more than one nucleoid surrounded with a common envelope. Despite this remarkable morphological difference, densities of the wild-type and S127 mutant virions were similar in cesium chloride gradients. The RNAs and proteins of mutant virions could not be distinguished from those of wild type on the basis of size or charge.

Incorporation of labeled precursors into the RNA and proteins of lactic dehydrogenase virus

Lactic dehydrogenase virus was grown in primary mouse embryo cells and labeled with (3)H-uridine and (3)H-amino acids. Concentrated and purified virus was banded by isopycnic centrifugation in sucrose gradients, and infectivity and radioactivity were found to correspond at a density of 1.17 g/cm(3). The extracted viral RNA was resolved by electrophoresis in polyacrylamide-agarose mixed gels, and the mol wt was estimated to be 6.0 x 10(6).

Inhibition of replication of lactic dehydrogenase virus by actinomycin

Lactic dehydrogenase virus replicated rapidly in monolayers of primary mouse embryo cells and reached a titer of 10(8) mean infective dose per ml within 18 h after infection. Despite the high virus yield, cytopathology was not observed. Examination of the tissue culture media failed to reveal any evidence of interferon, but the virus was found to be as sensitive to mouse interferon as vesicular stomatitis virus. Incubation of mouse embryo cells with actinomycin D markedly inhibited viral replication, whereas cytosine-beta-d-arabinofuranoside and 5-fluorodeoxyuridine had no effect on replication. These findings indicate that new DNA synthesis is not required but suggest that the intact function of cellular DNA may be required for lactic dehydrogenase virus replication.