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R H Hall

Publications and source records attributed to R H Hall.

At least 55 records · Page 3Linked to original sources
PubMed1974

Isopycnic centrifugation of sheared L-cell chromatin in metrizamide gradients.

Isopycnic gradient centrifugation of L-929 cell chromatin in a 38% (W/V) metrizamide solution yields two distinct fractions. The fraction banding at a density of 1.24 gm/cm(2) (H chromatin) contains about 10% of the DNA present in the fraction banding at a density of 1.18 gm/cm(2) (L chromatin). Both fractions contain the same proportions of satellite to main band DNA's. Some differences can be seen in the DNA: protein ratios and types of proteins present in the H and L chromatin fractions.

Animals↗
PubMed1974

An RNA fraction in chromatin of L-929 cells associated with DNA.

The DNA of L-929 cell nuclei was examined for the presence of an RNA fraction hybridized to the DNA that could possibly serve a role in gene regulation. A low molecular weight ([unk]4.5S) RNA fraction was observed as an RNA-DNA complex in chromatin preparations subfractionated on a Cs(2)SO(4) density gradient. This RNA does not appear to be covalently attached to the DNA. Neither does it appear to be attached to the DNA via a protein component. The RNA is resistant to ribonuclease H but is slowly attached by ribonuclease A + Tl. A role for, as well as the nature of the attachment of this RNA to DNA is suggested.

Animals↗
PubMed1973

Cytokinins in Rhizopogon roseolus Secretion of N-[9-(beta-d-Ribofuranosyl-9H) Purin-6-Ylcarbamoyl]Threonine into the Culture Medium.

Rhizopogon roseolus excretes the transfer RNA component, N-[9-(beta-d-ribofuranosyl-9H) purin-6-ylcarbamoyl]threonine (Ado-CO-thr) into the culture medium. This compound was proposed to be the archetype of ureidopurines exhibiting cytokinin activity. The amount of Ado-CO-thr isolated from the medium is about one-twentieth the amount of ribosylzeatin that can be isolated.

Journal Article↗
PubMed1972

N-(Delta-Isopentenyl)adenosine: Its Occurrence as a Free Nucleoside in an Autonomous Strain of Tobacco Tissue.

Cytokinins from both the free nucleoside pool and the transfer RNA have been isolated and identified in a habituated strain of tobacco pith callus (Nicotiana tabacum [L] var. Wisconsin 38). The transfer RNA of this strain contains both N(6)-(Delta(2)-isopentenyl) adenosine and N(6)-(4-hydroxy-3-methylbut-2-cis-enyl) adenosine. The trans-hydroxylated derivative is absent from the transfer RNA of this dark-grown tissue. N(6)-(Delta(2)-Isopentenyl)-adenosine was identified as a component of the free nucleoside pool in concentrations of about 10 micrograms per kilogram of tissue.The cytokinin-requiring tissue grown in the presence of N(6)-furfurylaminopurine contains less than 85 nanograms per kilogram of N(6)-(Delta(2)-isopentenyl) adenosine. This is the detectable limit under the conditions of the experiment.

Journal Article↗