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Biomedical subjects

A V Bader

Publications and source records attributed to A V Bader.

8 recordsLinked to original sources
PubMed1978

Decreased alkaline phosphatase in cells transformed by rous sarcoma virus.

Chick embryo cells transformed by either of two strains of Rous sarcoma virus (Bryan high titer or Schmidt-Ruppin) have low levels of alkaline phosphatase activity compared with nontransformed chick embryo cells. Essentially no differences in acid phosphatase activity were observed between these transformed and nontransformed cells. A virus mutant, RSV-BH-Ta, induces temperature-dependent transformation in infected cells. At 41 degrees, the transformation-nonpermissive temperature, alkaline phosphatase activities were similar to those of chick embryo cells. Shifting these cells to 37 degrees resulted in a change to transformed morphology and a progressive loss of enzyme activity, requiring 18 to 24 hr to reach the level of transformed cells. Rat embryo cells transformed by murine sarcoma virus also contained lower alkaline phosphatase levels than did nontransformed cells. These observations suggest that decreased alkaline phosphatase activities may be a general property of transformed cells.

Alkaline Phosphatase↗
PubMed1976

Transformation of cells by rous sarcoma virus: cytoplasmic vacuolization.

Chick embryo cells transformed by the Bryan "high titer" strain of Rous sarcoma virus (RSV-BH) are heavily vacuolated. A variety of microscopic techniques have been used demonstrating that the vacuoles are cytoplasmic, bounded by membrane, and are composed largely of water. Proteins, lipids, glycoproteins, glycolipids, glycosaminoglycans, glycogen, and nucleic acids were undetectable in the vacuoles. Physiological requirements for development of the vacuoles, and reversal of vacuolization, were examined in cells infected with a virus mutant, RSV-BH-Ta, which induces reversible temperature-dependent transformation. Na+ was the only component of the cell culture medium found essential for both the development and reversal of vacuoles. Glucose depletion or dinitrophenol treatment inhibited vacuolization, suggesting a possible energy requirement in the vacuolization process. Ouabain, an inhibitor of Na+-K+ ATPase, enhanced vacuolization, but a variety of other substances affecting cell surface components were in active. Two sugars, glucosamine and mannosamine, prevented the disappearance of vacuoles. The observations suggest that cellular vacuolization may be a normal physiological response to an increase in water and Na+, and, in the specific case of transformation by RSV-BH, may be relevant to the physiological basis for malignancy.

Adenine↗
PubMed1973

Role of mitochondria in the production of RNA-containing tumor viruses.

The role of mitochondria in the reproduction of RNA-containing tumor viruses was examined by using ethidium bromide (EB) to induce degenerative effects in mitochondria. The effects of EB in murine and avian cells were monitored by electron microscopy. Chronically infected mouse (JLS-V5) cells, in which extensive mitochondrial changes were induced, continued to produce murine leukemia virus. Also, complete reproductive cycles of Rous sarcoma virus (RSV) occurred in newly infected chicken embryo cells exposed to EB. Morphological transformation characteristic of infection of chicken embryo cells by RSV occurred in cells which contained induced aberrant mitochondria. The results demonstrate that mitochondria play a relatively minor role, if any, in the reproduction of RNA-containing tumor viruses.

Animals↗
PubMed1970

Evidence for a DNA replicative genome for RNA-containing tumor viruses.

The requirement for DNA synthesis in the reproduction of RNA tumor viruses was examined using 5-bromodeoxyuridine (BrdU). Addition of BrdU for the first 12 hr after exposure of cells to Rous sarcoma virus resulted in a large decrease in infectious progeny. However, incorporation of [(3)H]uridine into the viral RNA of virions was unaffected. Also, the numbers of virions visualized by electron microscopy were similar in BrdU-treated and untreated samples. Viral group-specific antigen was synthesized after BrdU treatment, and BrdU had little effect on transformation of cells by Rous sarcoma virus. The results support the hypothesis that the replicative genome of RNA-containing tumor viruses contains DNA.

Antigens, Neoplasm↗