Isolation and characterization of a dihydropyrimidine dehydrogenase mutant of Pseudomonas chlororaphis

West, Thomas P.

doi:10.1007/bf00245401

Cited by 18 publications

(7 citation statements)

References 20 publications

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“…Some form of nitrogen control or substrate induction may be indicated. A several-fold increase in dihydropyrimidinase activity after growth on dihydrothymine as a nitrogen source has also been witnessed in P. pseudoalcaligenes [5] and Pseudomonas chlororaphis [18]. This dihydrothymine-mediated increase in activity would seem to be species-dependent since dihydropyrimidinase activity in Pseudomonas aeruginosa was unaffected by growth on dihydrothymine as a nitrogen source but was induced after growth on uracil [10].…”

Section: Resultsmentioning

confidence: 89%

“…Uracil degradation usually occurs by means of a reductive pathway in pseudomonads [10,17,18]. The pathway enzymes dihydropyrimidine dehydrogenase and dihydropyrimidinase are known to be active in members of the P. fluorescens and P. alcaligenes DNA homology groups [5,10,18,19]. The initial enzyme catalyzes the reduction of uracil or thymine to dihydrouracil or dihydrothymine, respectively [17].…”

Section: Resultsmentioning

confidence: 99%

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Pyrimidine base and ribonucleoside catabolic enzyme activities of the Pseudomonas diminuta group

West

1992

FEMS Microbiology Letters

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Pyrimidine base and ribonucleoside catabolic enzyme activities of the two type strains of the Pseudomonas diminuta group were investigated for taxonomic classification purposes. The presence of the pyrimidine salvage enzyme nucleoside hydrolase was indicated in both type strains following thin-layer chromatographic analysis. The presence of the hydrolase was also confirmed by enzyme assay. In addition, the activities of the pyrimidine salvage enzymes dihydropyrimidine dehydrogenase and dihydropyrimidinase were measurable in cell-free extracts of both P. diminuta and P. vesicularis. An absence of cytosine deaminase activity was found when assaying extracts of the two type strains. Nucleoside hydrolase and dihydropyrimidine dehydrogenase levels in P. vesicularis were influenced by carbon source while dihydropyrimidinase activity was observed to increase after P. diminuta growth on dihydrothymine as a nitrogen source.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Pyrimidine base and ribonucleoside catabolic enzyme activities of the Pseudomonas diminuta group

West

1992

FEMS Microbiology Letters

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“…Although sequencing of the E. histolytica genome has revealed the existence of a DPD homologue (Anderson and Loftus, ), nothing is known about its characteristics. In order to obtain information about this homologue, we measured the activity of DPD using a previously described DPD activity assay (West, ). Our results showed that E. histolytica DPD use NADH (specific activity of 1.4 μmol NADH min −1 mg −1 ) but not NADPH as a cofactor (no activity was detected with NADPH).…”

Section: Resultsmentioning

confidence: 99%

“…The activity of DPD enzyme was determined spectrophotometrically by monitoring for 5 min at OD 340 the decrease in absorbance that occurs when NADH is converted to NAD+ as reported previously (West, ). The reaction mixture contained 1 mM DTT, 0.2 mM NADH, 150 mM uracil and an E. histolytica cytoplasmic extract in PBS buffer (pH 7.4) in a final volume of 1 ml.…”

Section: Methodsmentioning

confidence: 99%

Identification of dihydropyrimidine dehydrogenase as a virulence factor essential for the survival ofEntamoeba histolyticain glucose-poor environments

et al. 2012

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SummaryAdaptation to nutritional changes is a key feature for successful survival of a pathogen within its host. The protozoan parasite Entamoeba histolytica normally colonizes the human colon and in rare occasions, this parasite spread to distant organs, such as the liver. E. histolytica obtains most of its energy from the fermentation of glucose into ethanol. In this study, we were intrigued to know how this parasite reacts to changes in glucose availability and we addressed this issue by performing a DNA microarray analysis of gene expression. Results show that parasites that were adapted to growth in absence of glucose increased their virulence and altered the transcription of several genes. One of these genes is the dihydropyrimidine dehydrogenase (DPD), which is involved in degradation of pyrimidines. We showed that this gene is crucial for the parasite's growth when the availability of glucose is limited. These data contribute to our understanding of the parasite's ability to survive in glucosepoor environments and reveal a new role for the DPD enzyme.

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“…Only a single study has explored pyrimidine base catabolism in P. chlororaphis ATCC 17414 [134], and it was shown that the reductive catabolic enzymes dihydropyrimidine dehydrogenase and dihydropyrimidinase were active in cells grown on glucose as a carbon source and ammonium sulfate as a nitrogen source [134]. It was found that the growth of ATCC 17414 on uracil, thymine, dihydrouracil or dihydrothymine as a nitrogen source and glucose as a carbon source increased the dihydropyrimidine dehydrogenase activity by at least 14-fold compared to its activity in ammonium sulfate-grown cells [134]. The growth of ATCC 17414 cells on uracil or dihydrothymine as a nitrogen source and glucose as a carbon source caused a 16.1-fold or 122-fold change, respectively, in dihydropyrimidinase activity relative to its activity in ammonium sulfate-grown cells [134].…”

Section: Pseudomonas Chlororaphis Homology Groupmentioning

confidence: 99%

Pyrimidine Biosynthesis and Ribonucleoside Metabolism in Species of Pseudomonas

West

2023

Fermentation

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Pyrimidine biosynthesis and ribonucleoside metabolism in species of Pseudomonas was the focus of this review, in relation to their current taxonomic assignments in different homology groups. It was of interest to learn whether pyrimidine biosynthesis in taxonomically related species of Pseudomonas was regulated in a similar fashion by pyrimidine base supplementation or by pyrimidine limitation of pyrimidine auxotrophic strains. It was concluded that the regulation of pyrimidine biosynthesis in Pseudomonas species could not be correlated with their taxonomic assignment into a specific homology group. Pyrimidine ribonucleoside metabolism in Pseudomonas species primarily involved the pyrimidine ribonucleoside salvage enzymes nucleoside hydrolase and cytosine deaminase, independently of the Pseudomonas homology group to which the species was assigned. Similarly, pyrimidine base catabolism was shown to be active in different taxonomic homology groups of Pseudomonas. Although the number of studies exploring the catabolism of the pyrimidine bases uracil and thymine was limited in scope, it did appear that the presence of the pyrimidine base reductive pathway of pyrimidine catabolism was a commonality observed for the species of Pseudomonas investigated. There also appeared to be a connection between pyrimidine ribonucleoside degradation and the catabolism of pyrimidine bases in providing a cellular source of carbon or nitrogen independently of which homology group the species of Pseudomonas were assigned to.

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Isolation and characterization of a dihydropyrimidine dehydrogenase mutant of Pseudomonas chlororaphis

Cited by 18 publications

References 20 publications

Pyrimidine base and ribonucleoside catabolic enzyme activities of the Pseudomonas diminuta group

Pyrimidine base and ribonucleoside catabolic enzyme activities of the Pseudomonas diminuta group

Identification of dihydropyrimidine dehydrogenase as a virulence factor essential for the survival ofEntamoeba histolyticain glucose-poor environments

Pyrimidine Biosynthesis and Ribonucleoside Metabolism in Species of Pseudomonas

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