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Pyrimidine nucleotide synthesis in the emerging pathogen Pseudomonas monteilii
Jayendra Chunduru1,1, Thomas P West1,1
1Department of Chemistry, Texas A&M University-Commerce, Commerce, TX 75429, USA.
Abstract:
Regulation of pyrimidine biosynthesis by pyrimidines in the emerging, opportunistic human pathogen Pseudomonas monteilii ATCC 700476 was evident. When wild-type cells were grown on succinate in the presence of uracil or orotic acid, the activities of all 5 pyrimidine biosynthetic enzymes were depressed while the activities of 3 of the enzymes decreased in glucose-grown cells supplemented with uracil or orotic acid compared with unsupplemented cells. Pyrimidine limitation of succinate- or glucose-grown pyrimidine auxotrophic cells lacking orotate phosphoribosyltransferase activity resulted in more than a doubling of the pyrimidine biosynthetic enzyme activities relative to their activities in uracil-grown cells. Independent of carbon source, pyrimidine-limited cells of the pyrimidine auxotrophic cells deficient for dihydroorotase activity generally resulted in a slight elevation or depression of the pyrimidine biosynthetic enzyme activities compared with their activities in cells grown under saturating uracil conditions. Aspartate transcarbamoylase activity in P. monteilii was regulated at the enzyme activity level, since the enzyme was strongly inhibited by CTP, UMP, GMP, GDP, ADP, and UTP. In summary, the regulation of pyrimidine biosynthesis in P. monteilii could be used to control its growth or to differentiate it biochemically from other related species of Pseudomonas.
Insights
Pyrimidine biosynthesis in Pseudomonas monteilii is regulated by pyrimidines. This regulation offers potential for controlling pathogen growth and biochemical differentiation.
Area of Science:
- Microbiology
- Biochemistry
Background:
- Pseudomonas monteilii is an emerging opportunistic human pathogen.
- Understanding its metabolic pathways, like pyrimidine biosynthesis, is crucial for controlling its growth.
Purpose of the Study:
- To investigate the regulation of pyrimidine biosynthesis in Pseudomonas monteilii.
- To determine if pyrimidine levels affect the activity of pyrimidine biosynthetic enzymes.
- To explore potential biochemical markers for differentiating P. monteilii.
Main Methods:
- Culturing wild-type and auxotrophic strains of P. monteilii under varying pyrimidine conditions (uracil, orotic acid).
- Measuring the activities of key pyrimidine biosynthetic enzymes.
- Assessing aspartate transcarbamoylase inhibition by various nucleotides.
Main Results:
- Pyrimidine supplementation (uracil, orotic acid) depressed pyrimidine biosynthetic enzyme activities in wild-type cells.
- Pyrimidine limitation significantly increased enzyme activities in auxotrophic cells lacking orotate phosphoribosyltransferase.
- Aspartate transcarbamoylase activity was inhibited by multiple pyrimidine and purine nucleotides.
Conclusions:
- Pyrimidine biosynthesis in P. monteilii is subject to feedback regulation by pyrimidines.
- Enzyme activity regulation, particularly of aspartate transcarbamoylase, plays a key role.
- These regulatory mechanisms could be exploited for controlling P. monteilii growth or for its biochemical identification.
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