Investigation of Pyrimidine Salvage Pathways to Categorize Indigenous Soil Bacteria of Agricultural and Medical Importance and Analysis of the Pyrimidine Biosynthetic Pathway's Enzyme Properties for Correlating Cell Morphology to Function in All Phases of Growth

This dissertation comprises three parts and is presented in two chapters. Chapter 1 concerns Arthrobacter, a bacterium with an intriguing growth cycle. Whereas most bacteria exist as either a rod or coccus, this bacterium shares the rod/coccus lifestyle. It therefore seemed important to examine the growth regulatory pathways from the rod and coccus. The committed step, that catalyzed by aspartate transcarbamoylase (ATCase), in the pyrimidine biosynthetic pathway was chosen. The ATCase in Arthrobacter is like the well known Pseudomonas enzyme except that it has an active dihydroorotase (DHOase) associated. Included in Chapter 1 is the description of a microorganism, Burkholderia cepacia, whose ATCase has characteristics that are at once reminiscent of bacteria, mammals, and fungi. It differs in size or aggregation based on environmental conditions. In addition, it has an active DHOase associated with the ATCase, like Arthrobacter. B. cepacia is important both medically and for bioremediation. Since B. cepacia is resistant to most antibiotics, its unique ATCase is a prime target for inhibition. Whereas the first chapter deals with the de novo pathway to making pyrimidines, which is found mainly in the lag and log phase, Chapter 2 addresses the salvage pathway, which comes more into play during the stationary phase. This section focuses on the isolation, identification, and grouping of a number of natural soil bacteria from various soil locations. These organisms are important agriculturally, medically, and industrially. Addition of these soil isolates to poor soils has been found to improve the soil. In a previous study by D.A. Beck, the salvage schemes for a number of laboratory strains of microorganisms were determined. Nine separate classes of salvage were designated by determining the salvage enzymes present. In this study emphasis has been placed on soil bacteria, which had not previously been analyzed. A number of species of soil bacteria were identified using the MIDI. The salvage enzymes were then determined for these organisms and a comparison of these isolates to the previous study was performed in order to group the new organisms into 19 salvage schemes, that is 10 more than in the previous study.

Grantor dc:publisher

University of North Texas

Year dc:date

2003

Author dc:creator

• Meixner, Jeffery Andrew

Contributors dc:contributor

• O'Donovan, Gerard A.
• Benjamin, Robert C.
• Beck, Debrah A.
• Knesek, John
• Shanley, Mark S.

• Pyrimidines.
• Biosynthesis.
• Soil microbiology.
• Pyrimidine biosynthesis and salvage
• pristine soil bacteria
• ATCase-DHOase complex
• dihydroorotase
• coccus interchange

Statement dc:rights

• Public
• Copyright
• Meixner, Jeffery Andrew
• Copyright is held by the author, unless otherwise noted. All rights reserved.

Language dc:language

English

Identifier

oclc: 53215340
https://digital.library.unt.edu/ark:/67531/metadc4194/
ark: ark:/67531/metadc4194

OAI identifier oai:identifier

info:ark/67531/metadc4194