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dc.contributor.advisorSeed, J. R.
dc.creatorHall, James Edwin
dc.descriptionTypescript (photocopy).en
dc.description.abstractAromatic amino catabolism by Trypanosoma brucei gambiense, the protozoan parasite causing African sleeping sickness, has been suggested to contribute to pathogenesis in trypanosomiasis and to be pysiologically important to bloodstream trypanosomes. The pathways may also prove useful in developing new diagnostic assays of the disease. In a continuing study of these possibilities, gas liquid chromatographic procedures were developed to quantify aromatic amino acid catabolites formed by T. b. gambiense in vitro and excreted by host animals during acute laboratory infections of Microtus montanus. The current results confirm that T. b. gambiense catabolizes tryptophan in vitro to indole-3-acetic acid, indole-3-lactic acid and indole-3-ethanol (tryptophol), with indole-3-acetic acid predominating under the fully aerated incubation conditions used in the present study. Significant quantities of chemically unstable indole-3-pyruvic acid, previously suggested to be an intermediate of the pathway, were observed to accumulate in the incubates. Three related trypanosome species, T. equiperdum, T. lewisi and T. musculi, catabolized tryptophan similarly in vitro, although different end products were formed. T. b. gambiense and T. equiperdum, members of the subgenus Trypanozoon, formed all four indole products, while T. lewisi and T. musculi, members of the subgenus Herpetesoma, formed only indole-3-lactic acid. The patterns of catabolites produced may relate to different oxidative metabolic potentials of the two subgenera. A marked disturbance in aromatic amino acid catabolism was detected in both acute and chronic infections of laboratory rodents. Large increases in urinary excretion of phenylpyruvic acid, 4-hydroxyphenylpyruvic acid and the indole catabolites, indole-3-pyruvic acid, indole-3-lactic acid and indole-3-acetic acid, were observed. No indole-3-ethanol was detected in urine of infected or control animals. The excretory profile is similar to that found in the metabolic disorder phenylketonuria...en
dc.format.extentix, 70 leavesen
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subjectMajor biologyen
dc.subject.classification1979 Dissertation H177
dc.subject.lcshAfrican trypanosomiasisen
dc.titleTrypanosome metabolism of aromatic amino acids : quantification of catabolites formed in vitro and in two rodent model systems in vivoen
dc.typeThesisen A&M Universityen of Philosophyen Den
dc.format.digitalOriginreformatted digitalen
dc.publisher.digitalTexas A&M University. Libraries

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