Search PubMed⌕ Search

Biomedical subjects

G Coleman

Publications and source records attributed to G Coleman.

At least 73 records · Page 4Linked to original sources
PubMed1977

The characteristics of extracellular protein secretion by Staphylococcus aureus (Wood 46) and their relationship to the regulation of alpha-toxin formation.

The progress of secretion of alpha-toxin and total extracellular protein by Staphylococcus aureus (Wood 46), grown aerobically at 37 degrees C, in a 3% (s/v) tryptone soya broth medium supplemented with vitamins was followed. Exoprotein was secreted at a high rate by intact bacteria during the exponential phase (to 9 h) and into the post-exponential phase. After 18 h, when exoprotein accounted for 33% of the total protein in the culture, no further exoprotein was secreted although the bacterial density continued to increase at a low rate beyond this time. During the phase of active secretion, alpha-toxin represented a constant proportion of total exoprotein, the differential rate of synthesis of which increased by a factor of four after the end of exponential growth. Concomitant with the increase in the differential rate of exoprotein formation there was a fourfold increase in the intracellular concentration of RNA precursor material.

Bacterial Proteins↗
PubMed1977

Comparison of the patterns of increased in alpha-toxin and total extracellular protein by Staphylococcus aureus (Wood 46) grown in media supporting widely differing growth characteristics.

A comparison has been made of total exoprotein formation by Staphylococcus aureus (Wood 46) in a tryptone soya broth (TSB) medium and a casein hydrolysate-yeast extract-containing (CCY) medium in which exponential growth occurred with doubling times of 3.0 and 1.3 h, respectively. It was found that the differential rate of exoprotein formation was biphasic in each case, increasing after the cessation of exponential growth by a factor of 4 in TSB and 7 in CCY medium. Although this relative change was greater in CCY medium, the maximum value of the differential rate was less than 40% of that achieved in TSB medium. It was further shown that throughout the growth cycle, and in both cultures, alpha-toxin accounted for the same proportion of total extracellular protein.

Bacterial Proteins↗
PubMed1976

The effect of rifampicin on the stability of the messenger ribonucleic acid of Bacillus amyloliquefaciens as determined by DNA:RNA hybridization.

Rifampicin at a concentration of 10 mug/ml completely inhibited protein synthesis in exponential-phase cultures of Bacillus amyloliquefaciens. At this same concentration the drug was shown to have no effect on the stability of mRNA, determined as the functional and hybridizable material, when compared with hybridizable mRNA in an uninhibited system. In each case, the half-life of the mRNA had a value in the range 5 +/- 1 min, at 30 degrees C.

Bacillus↗
PubMed1976

Life in death.

Explore the source record for details and available documents.

Nursing, Practical↗
PubMed1972

A study of the nature of the immediate precursor of the extracellular -amylase of Bacillus amyloliquefaciens. A reappraisal.

1. A defined medium was devised for use in washed-cell experiments with post-exponential-phase cultures of Bacillus amyloliquefaciens. The medium allowed alpha-amylase to be secreted, bacterial concentration to increase and l-[U-(14)C]valine to be incorporated into protein at a linear rate, which was the same as in a post-exponential-phase culture, for up to 6h. 2. Determination of the specific radioactivity of l-[U-(14)C]valine in the medium, the intracellular amino acid pool, the cellular protein and the isolated alpha-amylase, after a 3h incubation of washed cells in the defined medium, showed that at least 76% of the alpha-amylase secreted was synthesized de novo. 3. By isolating the alpha-amylase formed during a 6h incubation in the presence of l-[U-(14)C]valine it was shown that the specific radioactivity of the N-terminal valine, within the limits of experimental error, was the same as that of the total valine residues from the complete alpha-amylase molecule. 4. A consideration of these results in relation to the whole literature on the subject strongly supports the idea that there is no reason to suppose that extracellular alpha-amylase is formed from a high-molecular-weight precursor in B. amyloliquefaciens and closely related organisms with identical characteristics of exoenzyme secretion.

Amino Acids↗