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M BEER

Publications and source records attributed to M BEER.

18 recordsLinked to original sources
PubMed1962

Effect of concentration on the formation of molecular hybrids from T4 DNA.

When the thymine of T(4) DNA is replaced by 5-BU the melting temperature of T(4) DNA is increased from about 83 degrees to about 93 degrees C. Heating and slow cooling of T(4) DNA at concentrations of about 30 mug/ml leads to aggregates which consist of several polynucleotide chains which appear in the electron microscope as a branched structure. The aggregates have regions which are true hybrids. When the concentration of T(4) DNA is lowered to less than 1 mug/ml the products of hybridization are not aggregates but have the morphology of native DNA molecules and the density labels are distributed as expected from the fusing of two chains of approximately equal length.

Bacteriophages↗
PubMed1961

Electron stains. I. Chemical studies on the interaction of DNA with uranyl salts.

Chemical studies have been carried out on the interaction of DNA with uranyl salts. The effect of variations in pH, salt concentration, and structural integrity of the DNA on the stoichiometry of the salt-substrate complex have been investigated. At pH 3.5 DNA interacts with uranyl ions in low concentration yielding a substrate metal ion complex with a UO(2) (++)/P mole ratio of about (1/2) and having a large association constant. At low pH's (about 2.3) the mole ratio decreases to about (1/3). Destruction of the structural integrity of the DNA by heating in HCHO solutions leads to a similar drop in the amount of metal ion bound. Raising the pH above 3.5 leads to an apparent increase in binding as does increasing the concentration of the salt solution. This additional binding has a lower association constant. Under similar conditions DNA binds about seven times more uranyl ion than bovine serum albumin, indicating useful selectivity in staining for electron microscopy.

Coloring Agents↗