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N N DURHAM

Publications and source records attributed to N N DURHAM.

At least 19 recordsLinked to original sources
PubMed1963

INHIBITION OF MICROBIAL GROWTH AND SEPARATION BY D-SERINE, VANCOMYCIN, AND MITOMYCIN C.

Durham, Norman N. (Oklahoma State University, Stillwater). Inhibition of microbial growth and separation by d-serine, vancomycin, and mitomycin C. J. Bacteriol. 86:380-386. 1963.-A study was made of the growth and separation inhibition of Pseudomonas fluorescens by vancomycin and mitomycin C and of a Flavobacterium sp. sensitive to mitomycin C and d-serine. Aberrant morphological forms (primarily "boat-shaped" cells and "chain-like" filaments) were observed during growth of the sensitive organism in the presence of the inhibitors. Reversal studies indicated that Mg(++), and to a lesser extent Mn(++), partially reversed vancomycin and mitomycin C growth inhibition during the early stages of growth but did not influence d-serine inhibition. Selected metabolites also showed a tendency to partially reverse mitomycin C and vancomycin inhibition of growth during the initial growth phase, and the differences in reversal trends suggested that d-serine, vancomycin, and mitomycin C produce metabolic lesions at different sites in the cell with respect to growth. Cultivation of the sensitive organism in low concentrations of the inhibitors resulted in a structurally fragile population, indicating formation of a defective cell structure. Mg(++) partially reversed the vancomycin inhibition of separation in these organisms. None of the other metals or metabolites, either singly or in varied combinations, was able to reverse inhibition of separation by the various inhibitors.

Flavobacterium↗
PubMed1961

Competitive relationship between protocatechuic acid and p-aminosalicylic acid for a cellular transport mechanism.

Hubbard, Jerry S. (Oklahoma State University, Stillwater), and Norman N. Durham. Competitive relationship between protocatechuic acid and p-aminosalicylic acid for a cellular transport mechanism. J. Bacteriol. 82:361-369. 1961.-The oxidation of protocatechuic acid by a Flavobacterium is inhibited by p-aminosalicyclic acid regardless of whether the organism is grown on protocatechuic acid or sequentially induced to protocatechuic acid by growth on p-aminobenzoic acid. Depletion of the substrate from the medium by the cell suspension is dependent, within defined limits, on the inhibitor to substrate ratio, and the inhibition can be overcome by addition of excess substrate. However, this competitive effect is not observed in high inhibitor to substrate ratios. p-Aminosalicylic acid did not affect the rate or extent of oxidation, carbon dioxide evolution, or formation of beta-ketoadipic acid during degradation of protocatechuic acid by cell extracts. The results suggest that p-aminosalicylic acid antagonizes the oxidation of protocatechuic acid by the cell suspension by competing with the substrate for a specific transport mechanism, thereby regulating the entry and internal accumulation of the substrate. The lack of a competitive effect in high inhibitor to substrate ratios could be interpreted as an indication that the mechanism for accumulating the substrate may consist of more than one active transport system.

4-Aminobenzoic Acid↗