Trimethylamine-N-oxide (TMA-0) reductase activity of resting cells of Escherichia coli was inhibited by tetrasodium ethylenediaminetetraacetate (Na₄EDTA), benzoic acid (BA), and methylparaben (MP). The 50% inhibitory concentrations of Na₄EDTA, BA, and MP were 20.2, 1.2, and 32.4 mM, respectively. BA at pH 6.5 or below most effectively inhibited the TMA-0 reductase. Sorbic acid (SA), up to 0.70 mM, had no effect on TMA-0 reductase activity, but SA inhibited the growth and subsequent TMA production in E. coli at or above 0.35 mM. / Graduation date: 1981

Investigations have been made on the purification of Clostridium botulinum type E toxin and an attempt made to elucidate the phenomenon of trypsin activation. Type E botulinus toxin produced in meat infusion medium in dialysis sacs was partially purified by Seitz filtration and ethanol precipitation. Treatment of this toxic preparation with trypsin produced a 20 - 50 fold increase in potency. Both non-activated and trypsin-activated toxins were further purified by elution through cellulose ion-exchange columns and dried by lyophilization. Refractionation of these dried toxins effected even further purity. These highly purified preparations of both non-activated and trypsin-activated type E toxin were then analysed in the ultracentrifuge. The former was found to have a sedimentation constant of 5.6 Svedburg units whereas activated toxin did not form a boundary under identical conditions. Together with other considerations, this evidence indicates that the activation mechanism involves a fragmentation process whereby more toxic sites become exposed on the toxin molecule. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1966. / Bibliography: leaves [77]-79. / ix, 79 l illus., tables

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1973. / Bibliography: leaves [367]-370. / xxv, 370 l illus., graphs, tables

Typescript. / Bibliography: leaves 108-110. / xiii, 242 l illus

Thesis (M.Sc.) -- University of Adelaide, Department of Human Physiology and Pharmacology, 1971.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2005. / Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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