Man lacks a biochemical pathway for synthesis of aromatic amino acids. Thus, L-tyrosine, L-phenylalanine, L-tryptophan and vitamin-like derivatives of the pathway must be supplied externally. Pseudomonas aeruginosa requires this multi-branched, complicated pathway as a source of the latter essential metabolites as well as for pyocyanine pigment and iron-binding siderophores. Thus, an ideal basis exists for manipulation of the host-pathogen relationship since a multiplicity of enzyme targets exist in P. aeruginosa that are absent altogether in the host tissues. Additional applications are suggested by consideration of the metabolic interfaces of the pathway with carbohydrate metabolism and with catabolic networks. Aromatic endproducts are biochemically expensive to make and strategies of """"""""energy drain"""""""" that exhaust energy resources will be pursued using the mid-pathway inhibitor, glyphosate. Design of a stable substrate mimic of pathway dehydrogenase/dehydratase enzymes will be pursued. Modified genetic backgrounds or physiological conditions that block an anomalous phenomenon of endproduct depletion will be sought in order to facilitate mutant-isolation objectives. The possibility that """"""""catabolic"""""""" depletion is important to the pathobiological mode of P. aeruginosa will be evaluated. Continuation of the previous objectives to obtain a complete set of structural-gene and regulatory-gene mutants will be carried out with the objective of understanding gene-enzyme relationships from a comprehensive vantage point that includes physiological, biochemical and molecular-genetic levels. P. aeruginosa is noteworthy for its resistance to antimetabolite therapy. It is also commonly resistant to analog mimics of phenylalanine and tyrosine. Analog sensitivity can readily be achieved through manipulation of metabolic conditions. Specific understanding of the aromatic system may generalize to the nature of high antimetabolite resistance typical of P. aeruginosa.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK038309-05
Application #
3237595
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1986-07-01
Project End
1993-06-30
Budget Start
1990-07-01
Budget End
1991-06-30
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Florida
Department
Type
Schools of Arts and Sciences
DUNS #
073130411
City
Gainesville
State
FL
Country
United States
Zip Code
32611
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Xia, T; Zhao, G; Jensen, R A (1993) The pheA/tyrA/aroF region from Erwinia herbicola: an emerging comparative basis for analysis of gene organization and regulation in enteric bacteria. J Mol Evol 36:107-20
Xia, T; Song, J; Zhao, G et al. (1993) The aroQ-encoded monofunctional chorismate mutase (CM-F) protein is a periplasmic enzyme in Erwinia herbicola. J Bacteriol 175:4729-37
Zhao, G; Xia, T; Aldrich, H et al. (1993) Cyclohexadienyl dehydratase from Pseudomonas aeruginosa is a periplasmic protein. J Gen Microbiol 139:807-13
Xia, T; Jensen, R A (1992) Monofunctional chorismate mutase from Serratia rubidaea: a paradigm system for the three-isozyme gene family of enteric bacteria. Arch Biochem Biophys 294:147-53
Xia, T H; Ahmad, S; Zhao, G S et al. (1991) A single cyclohexadienyl dehydratase specifies the prephenate dehydratase and arogenate dehydratase components of one of two independent pathways to L-phenylalanine in Erwinia herbicola. Arch Biochem Biophys 286:461-5
Fischer, R S; Zhao, G; Jensen, R A (1991) Cloning, sequencing, and expression of the P-protein gene (pheA) of Pseudomonas stutzeri in Escherichia coli: implications for evolutionary relationships in phenylalanine biosynthesis. J Gen Microbiol 137:1293-301
Hendry, A T; Bhatnagar, R K; Shanmugam, K T et al. (1990) Exploitation of the broad specificity of the membrane-bound isoenzyme of lactate dehydrogenase for direct selection of null mutants in Neisseria gonorrhoeae. J Gen Microbiol 136:45-50
Bonner, C A; Fischer, R S; Ahmad, S et al. (1990) Remnants of an ancient pathway to L-phenylalanine and L-tyrosine in enteric bacteria: evolutionary implications and biotechnological impact. Appl Environ Microbiol 56:3741-7
Coleman, J B; Casini, A F; Serroni, A et al. (1990) Evidence for the participation of activated oxygen species and the resulting peroxidation of lipids in the killing of cultured hepatocytes by aryl halides. Toxicol Appl Pharmacol 105:393-402

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