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Biomedical subjects

A Weissbach

Publications and source records attributed to A Weissbach.

At least 73 records · Page 4Linked to original sources
PubMed1972

A new synthetic RNA-dependent DNA polymerase from human tissue culture cells (HeLa-fibroblast-synthetic oligonucleotides-template-purified enzymes).

Two DNA polymerases that can copy synthetic RNA polymers are present in human tissue culture cells. These enzymes which have each been purified about 500-fold, are present in both HeLa cells, which are derived from a cervical carcinoma, and in WI-38 cells, a normal diploid strain originating from human embryonic lung tissue. These synthetic RNA-dependent DNA polymerases are identified by their ability to copy efficiently the ribo strand of synthetic oligonucleotide-homopolymer complexes, and differ in this respect from the known DNA-dependent DNA polymerases found in HeLa cells. The template requirements of these new DNA polymerases resemble that of the RNA-dependent DNA polymerases of the RNA tumor-viruses.

Cell Line↗
PubMed1972

Deoxyribonucleic acid polymerase activities in normal and leukovirus-infected chicken embryo cells.

Chicken embryo cells normally contain, in addition to deoxyribonucleic acid (DNA)-dependent DNA (D-DNA) polymerases, a novel "R-DNA-polymerase" which specifically copies polyriboadenylic acid strands. This R-DNA polymerase cannot copy natural ribonucleic acid or polyribocytidylic acid strands to a significant extent. Infection of cells with the leukovirus RAV-2 leads to the intracellular formation of large amounts of the viral RNA-dependent DNA polymerase whose properties differ from the cell R-DNA polymerase. Chicken cells transformed by a Rous sarcoma virus mutant which produce noninfectious alpha-type Rous sarcoma virus (f), a leukovirus known to be deficient in the viral RNA-dependent DNA polymerase, do not contain detectable viral RNA-dependent DNA polymerase, whereas the cellular R-DNA polymerase is found in normal amounts. There seems to be no relationship between the cellular R-DNA polymerase and the RNA-dependent DNA polymerase of the avian leukoviruses.

Animals↗
PubMed1972

Studies on vaccinia virus-directed deoxyribonucleic acid polymerase.

A vaccinia-directed deoxyribonucleic acid (DNA) polymerase has been partially purified from the cytoplasmic fractions of virus-infected HeLa cells. The utilization of natural and synthetic templates by this enzyme resembles that of the host cell DNA-dependent DNA polymerases. The vaccinia DNA polymerase cannot copy ribopolymers or ribonucleic acid but is very effective with an "activated" DNA as template. An exonuclease preferring single-stranded DNA as substrate is found in the most highly purified preparations of the enzyme. The molecular weight of the vaccinia DNA polymerase seems to be about 110,000. The viral DNA polymerase is also found to be associated with purified, infected cell nuclei, and this association may be due, at least in part, to nonspecific adsorption of the vaccinia DNA polymerase by nuclei.

Animals↗
PubMed1971

DNA polymerases of tumor virus: specific effect of ethidium bromide on the use of different synthetic templates.

The DNA polymerase enzymes from avian, murine, and feline RNA tumor viruses can be distinguished by their ability to read specific, synthetic primertemplates. The copying of templates containing adenylic and thymidylic acids by all these DNA polymerases is inhibited by ethidium bromide, though this compound affects the polymerases from mammalian tumor viruses much more than the enzyme from avian tumor viruses. Conversely, ethidium bromide stimulates the ability of the enzymes from avian tumor viruses to use primertemplates containing only guanylic and cytidylic acids, whereas the mammalian tumor virus enzymes are moderately inhibited.

Animals↗
PubMed1969

The bacteriophages.

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Antibiotics, Antineoplastic↗