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Biomedical subjects

J C MacDonald

Publications and source records attributed to J C MacDonald.

6 recordsLinked to original sources
PubMed1990

Graph-set analysis of hydrogen-bond patterns in organic crystals.

A method is presented based on graph theory for categorizing hydrogen-bond motifs in such a way that complex hydrogen-bond patterns can be disentangled, or decoded, systematically and consistently. This method is based on viewing hydrogen-bond patterns topologically as if they were intertwined nets with molecules as the nodes and hydrogen bonds as the lines. Surprisingly, very few parameters are needed to define the hydrogen-bond motifs comprising these networks. The methods for making these assignments, and examples of their chemical utility are given.

Chemical Phenomena↗
PubMed1978

Effect of weak magnetic fields on growth of cells in tissue culture.

Normal Chinese hamster V79 cells were grown in vitro for more than one year in a magnetic field of 10(-7) tesla to test recently hypothesized effects of weak magnetic fields on biological systems. No significant difference was observed between growth rate in such fields and that in the ambient geomagnetic field.

Cell Division↗
PubMed1977

Biosynthesis of arglecin and related compounds.

The requirements for maximum production of arglecin, 3-isobuty1-6-(3-guanidinopropyl)-2(1H)pyrazinone, by Streptomyces toxytricini grown on either yeast extract or synthetic medium were supplements of L-arginine and L-leucine. The arglecin produced was derived to a major extent from these amino acids, as was shown by comparison of specific activities in 14C-labeling experiments. Various compounds related to arglecin could be synthesized by the organism, and these were isolated and their structures determined primarily by natural-abundance carbon-13 and proton magnetic resonance methods. In old cultures which had produced arglecin, the metabolite 3-isobuty1-6-(3-aminopropy1)-2(1H)pyrazinone was found. In cultures grown on synthetic medium supplemented with L-leucine and L-homoarginine, the metabolit 3-isobuty1-6(4-guanidinobuty1)-2-(1H)pyrazinone was found, and in cultures that had been supplemented with L-norleucine and L-arginine, the metabolite 3-buty1-6-(3-guanidinopropy1)-2(1H)pyrazinone was found.

Arginine↗