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D G Moore

Publications and source records attributed to D G Moore.

23 records · Page 2Linked to original sources
PubMed1981

Specific inhibition of Escherichia coli ferrienterochelin uptake by a normal human serum immunoglobulin.

Normal human serum contains an enterochelin-specific antibody which presumably acts with transferrin to hinder iron assimilation by enterochelin-producing pathogens. This antibody can be isolated from serum by sodium sulfate fractionation or affinity chromatography by employing an enterochelin-derived ligand (2,3-dihydroxy-N-benzoyl-L-serine) attached to aminohexyl Sepharose 4B. In assays of iron uptake by whole cells, the antibody inhibited enterochelin-directed uptake but not that mediated by citrate or ferrichrome. Also, the growth stimulatory effect of enterochelin on an Ent- strain of Escherichia coli was blocked by the immunoglobulin. This antibody has a high affinity for enterochelin; various elution procedures employing high salt concentrations and low pH failed to remove it from affinity columns. Elution with 3 M sodium thiocyanate or 13 mM 2,3-dihydroxybenzoic acid proved successful. Two pieces of evidence indicate the enterochelin-specific antibody is primarily of the immunoglobulin A (IgA) isotype. It could be removed from serum with goat antihuman IgA and was present only in sodium sulfate fractions of serum known to contain IgA.

Antibodies, Bacterial↗
PubMed1980

Bacteriostatic enterochelin-specific immunoglobulin from normal human serum.

Heat-inactivated normal human serum produces iron-reversible bacteriostasis of a number of microorganisms. This inhibitory effect was abolished by adsorption of serum with ultraviolet-killed cells of species that produce the siderophore enterochelin. Bacteriostasis also was alleviated by adsorption of serum with 2,3-dihydroxy-N-benzoyl-L-serine, a degradation product of enterochelin, bound to the insoluble matrix AH-Sepharose 4B. The adsorption process did not add iron or enterochelin to serum, nor did it remove transferrin. The immunoglobulin fraction from normal human serum was isolated; when added to a defined medium (M199) prepared so as to mimic normal human serum, the immunoglobulin rendered the medium inhibitory to an enterochelin-defective strain of Salmonella typhimurium. Adsorption of this medium with AH-Sepharose 4B-2,3-dihydroxy-N-benzoyl-L-serine removed the inhibition. Our results indicate that enterochelin-specific immunoglobulins exist in normal human serum. These immunoglobulins may act synergistically with transferrin to effect bacteriostasis of enterochelin-producing pathogens.

Adsorption↗
PubMed1980

DDT residues in forest floors and soils of western Oregon, September-November 1966.

Between 1945 and 1965, 1.82 million hectares, or about 17 percent of the total commercial forestland in Oregon, were treated with 2.02 million kg DDT. Detectable residues of this insecticide might be present in forest soils, even those which have never received a direct application of insecticide. Forest floor and mineral soil samples were collected along four east-west transects across the Coast and Cascade Ranges. DDT residues were found in all samples, even though all but one site had never received a direct application of insecticide. In the Coast Ranges, mean concentrations of sigma DDT in forest floor samples were 0.049 ppm at the coast and 0.047, 0.064, 0.075, and 0.119 ppm at 16, 32, 48, and 64 km inland, respectively. Mean residue levels in the surface layers of mineral soil were much lower, 0.009 ppm and 0.006 ppm in the 0 to 7.5-cm and 7.5 to 15-cm depths, respectively. Sampling sites along the Cascade Range transects were selected on the basis of elevation except that the eastern site of each transect was located 16 km east of the crest of the Cascades. Residue concentrations in forest floor samples were three to four times higher than in the Coast Ranges, but were still below 0.50 ppm. In general, sigma DDT levels increased with increasing elevation up to 1,372 meters and then decreased quite sharply east of the crest. Variations can be explained on the basis of total rainfall distribution and by transect location relative to agricultural and metropolitan centers.

DDT↗