Document Type

Thesis - University Access Only

Award Date


Degree Name

Doctor of Philosophy (PhD)

Department / School



This study was undertaken to conduct a taxonomic comparison of pyrimidine biosynthesis in Pseudomonas putida, Pseudomonas a/caligenes, and Pseudomonas mendocina representing the three Pseudomonas DNA homology groups. These strains were characterized and the levels of the biosynthetic pathway enzyme activities were determined. This study also involved the isolation of uracil-requiring mutant strains from their wild type strains. After assaying extracts, the levels of the biosynthetic pathway enzyme activities were determined in each mutant strain and the strains were found to be deficient for orotate phosphoribosyltransferase activity. The findings provided evidence that differences exist at the transcriptional level between the three species with respect to the regulation of the de novo pyrimidine biosynthetic pathway enzyme activities when glucose or succinate served as the carbon source. It was also found that the in vitro regulation of aspartate transcarbamoylase activity could be used to taxonomically compare the species classified within the Pseudomonas DNA homology groups. Overall, this study indicated that an analysis of the regulation of pyrimidine biosynthesis in the species assigned to the Pseudomonas DNA homology groups could be used during the ongoing taxonomic evaluation of pseudomonads.

Library of Congress Subject Headings

Pseudomonas -- Classification
Pyrimidines -- Synthesis



Number of Pages



South Dakota State University