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Biomedical subjects

M Wright

Publications and source records attributed to M Wright.

At least 307 records · Page 17Linked to original sources
PubMed1971

Noradrenaline uptake by non-innervated smooth muscle.

1. Uptake of noradrenaline (NA) into the non-innervated smooth muscle cells of the human umbilical artery and the chick amnion has been studied with the fluorescence histochemical technique for localizing monoamines. Comparison has been made with uptake into sympathetically innervated smooth muscle of the rabbit ear artery.2. Accumulation of NA within non-innervated smooth muscle cells is observed histochemically after exposure to much lower concentrations of NA (10(-7) g/ml) than in sympathetically innervated smooth muscle cells, where accumulation occurs with NA (10(-5) g/ml).3. In contrast to innervated smooth muscle, uptake of NA (10(-4) g/ml) by non-innervated smooth muscle is characterized by lack of inhibition by phenoxybenzamine, normetanephrine and cold, although some inhibition is apparent at lower NA concentrations. Retention of NA during prolonged washing in NA-free Krebs demonstrates that it is strongly bound within the non-innervated smooth muscle cells, particularly in the nucleus.4. After inhibition of catechol-O-methyl transferase, the accumulation of NA in innervated smooth muscle closely resembles that in non-innervated smooth muscle.

Amnion↗
PubMed1971

Mutants of Escherichia coli lacking endonuclease I, ribonuclease I, or ribonuclease II.

To isolate mutants of Escherichia coli K-12 lacking endonuclease I activity (end), a method has been developed which detects, by differential methyl green staining, undegraded deoxyribonucleic acid (DNA) in colonies previously incubated in toluene. This procedure allows isolation of mutant strains in which DNA degradation is reduced. For half of these strains, this defect has been correlated with deficiencies of endonuclease I, ribonuclease I (rns), or ribonuclease II (rne) activities. The enzymatic deficiencies of the other strains remain unknown. An rne mutation is cotransducible with serA (which is located at 56 min on the genetic map). Most end mutations, called endA, are also cotransducible with serA and are located between serA and strA. One end mutation, called endB, is located between purE and trp (i.e., between 13 and 25 min on the genetic map).

Cell-Free System↗