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Biomedical subjects

J Vinograd

Publications and source records attributed to J Vinograd.

At least 55 records · Page 3Linked to original sources
PubMed1969

The use of an ethidium analogue in the dye-buoyant density procedure for the isolation of closed circular DNA: the variation of the superhelix density of mitochondrial DNA.

The separation between open and closed circular DNA in buoyant CsCl gradients containing intercalating dyes depends on the superhelix density of the closed form. These separations are about 1.8 times larger with propidium iodide than with ethidium bromide. The superhelix densities of mitochondrial DNA from HeLa cells and Lytechinus pictus eggs appear to be about two thirds that of mitochondrial DNA from rat and rabbit liver.

Animals↗
PubMed1969

Complex mitochondrial DNA in leukemic and normal human myeloid cells.

Mitochondrial DNA's from the peripheral blood of 14 patients with granulocytic leukemia contained a circular dimer form. No such structure could be found in M DNA's from three patients with nonmalignant proliferations of granulocytes. The frequency of the circular dimer form is reduced upon treatment with antileukemic drugs. The above results suggest that a significant relation exists between the formation and presence of the circular dimer M DNA form and granulocytic leukemia in man.

Busulfan↗
PubMed1966

Physical and topological properties of circular DNA.

Several types of circular DNA molecules are now known. These are classified as single-stranded rings, covalently closed duplex rings, and weakly bonded duplex rings containing an interruption in one or both strands. Single rings are exemplified by the viral DNA from phiX174 bacteriophage. Duplex rings appear to exist in a twisted configuration in neutral salt solutions at room temperature. Examples of such molecules are the DNA's from the papova group of tumor viruses and certain intracellular forms of phiX and lambda-DNA. These DNA's have several common properties which derive from the topological requirement that the winding number in such molecules is invariant. They sediment abnormally rapidly in alkaline (denaturing) solvents because of the topological barrier to unwinding. For the same basic reason these DNA's are thermodynamically more stable than the strand separable DNA's in thermal and alkaline melting experiments. The introduction of one single strand scission has a profound effect on the properties of closed circular duplex DNA's. In neutral solutions a scission appears to generate a swivel in the complementary strand at a site in the helix opposite to the scission. The twists are then released and a slower sedimenting, weakly closed circular duplex is formed. Such circular duplexes exhibit normal melting behavior, and in alkali dissociate to form circular and linear single strands which sediment at different velocities. Weakly closed circular duplexes containing an interruption in each strand are formed by intramolecular cyclization of viral lambda-DNA. A third kind of weakly closed circular duplex is formed by reannealing single strands derived from circularly permuted T2 DNA. These reconstituted duplexes again contain an interruption in each strand though not necessarily regularly spaced with respect to each other.

Bacteriophages↗