Biomedical subjects
M Gilmour
Publications and source records attributed to M Gilmour.
Genetic transfer of lactate-utilizing ability in the rumen bacterium Selenomonas ruminantium.
Matings between the lactate-utilizing, tetracycline-sensitive Selenomonas ruminantium strains 5521C1 and 5934e and the lactate-non-utilizing, tetracycline-resistant strain FB322 resulted in putative recombinant strains capable of growth on lactate. Analysis of total protein by SDS-PAGE and chromosomal DNA by hybridization, indicated that the recombinants were derived from strain FB322. DNA hybridization produced no evidence that plasmid transfer occurred, leaving chromosomal DNA transfer as the most likely mechanism for the altered phenotype. Analysis of strains 5934e, FB322 and the resulting recombinant TC3 indicated that all three strains contained D-nLDH and L-nLDH activities. In addition strains 5934e and TC3 possessed D-iLDH activity when grown on DL-lactate. The ability of strain FB322 to grow on pyruvate but not lactate suggested that the lactate-utilizing recombinant had acquired the ability to synthesize D-iLDH.
Multiple lactate dehydrogenase activities of the rumen bacterium Selenomonas ruminantium.
The lactate utilizing strain of Selenomonas ruminantium 5934e was found to contain three lactate dehydrogenase (LDH) activities in sonicated cell extracts. One activity, an NAD dependent L-LDH (L-nLDH) was measured at 15-fold greater levels in extracts of cells grown to mid-exponential phase on glucose compared to cells grown to the equivalent growth stage on DL-lactate. A second nLDH activity specific for D-lactate (D-nLDH) was detected at similar levels in both lactate-grown cell extracts and glucose-grown cell extracts. The third activity, an NAD independent DLDH (D-iLDH) was very low in cells grown on glucose but was induced more than 10-fold when DL-lactate was used as the carbon source. The three LDH activities could be separated by gel filtration. Recovery of the activities was low due to the apparent instability of the enzymes at 4 degrees C, which was most pronounced in the case of the D-iLDH. A Km for lactate of 0.5 mM was estimated for the D-iLDH and this was considerably lower than the values of 45 mM and 70 mM measured for L-nLDH and D-nLDH respectively. It is proposed that the D-iLDH may be largely responsible for the formation of pyruvate in lactate-grown cells of S. ruminantium strain 5934e. Three other lactate utilizing strains of S. ruminantium, HD4, 5521C1 and JW13 exhibited a similar profile of LDH activities to strain 5934e when grown on glucose and DL-lactate.
New Zealand and its doctors, 1840s-1980s.
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The disadvantaged student in nursing education.
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Gas chromatography as an aid in fermentation studies.
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