Metabolism of Pyrimidines and Pyrimidine Nucleosides by
            <i>Salmonella typhimurium</i>

Beck, Christoph F.; Ingraham, John L.; Neuhard, Jan; Thomassen, Elisabeth

doi:10.1128/jb.110.1.219-228.1972

Cited by 105 publications

(53 citation statements)

References 26 publications

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“…Indeed, the sensitivity of strain DG6 to FUR and the selection of spontaneous Furr mutants have been described previously (8). One plausible explanation for these mutants is the loss of UPRT activity (2).…”

Section: Resultsmentioning

confidence: 84%

“…The above result that fluoroorotate selects mutants lacking either OPRT (pyrE) or ODC and OPRT (pyrF) indicated that in S. acidocaldarius, as in other organisms, the 5-fluoro analog is metabolized in the same way as orotate and becomes deleterious only after conversion to 5-fluoro UMP (16). Similarly, blocking the formation of UMP from preformed nucleobases or nucleosides by inactivation of salvage enzymes would be expected to confer resistance to the corresponding 5-fluoro analogs (2). Indeed, the sensitivity of strain DG6 to FUR and the selection of spontaneous Furr mutants have been described previously (8).…”

Section: Resultsmentioning

confidence: 92%

“…As predicted by their generalized resistance, these fy mutants could be selected by any of several fluoropyrimidines. The biochemical basis for the phenotype is not the loss of UPRT activity (compare with upp mutants of E. coli [2]), but it does appear to involve overproduction and excretion of one or more pyrimidine compounds. This property is reminiscent of certain pyrH (UMP kinase-deficient) mutants of Escherichia coli, which exhibit abnormally high expression of ACT and other regulated de novo pathway enzymes (16).…”

Section: Discussionmentioning

confidence: 99%

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Sulfolobus acidocaldarius synthesizes UMP via a standard de novo pathway: results of biochemical-genetic study

Grogan

Gunsalus

1993

J Bacteriol

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A genetic approach was used to establish the route of UMP biosynthesis in Sulfolobus acidocaldarius, a member of the hyperthermophilic division (the Crenarchaeota) of the Archaea domain. Pyrimidine auxotrophs of S. acidocaldarius DG6 were isolated by direct selection and by brute-force methods. Enzymatic assay of extracts from wild-type S. acidocaldarius, from pyrimidine auxotrophs, and from phenotypic revertants demonstrated that S. acidocaldarius synthesizes UMP via orotate in six enzymatic steps corresponding to the de novo pathway of other organisms. The results also show that a single carbamoyl phosphate synthetase supplies both the pyrimidine and arginine pathways of this organism. To gain similar insight into pyrimidine salvage pathway(s), prototrophic mutants resistant to toxic pyrimidine analogs were also isolated and characterized. The results suggest that a single class of mutants which had acquired elevated resistance to four different 5-fluoropyrimidines had been isolated. These fluoropyrimidine-resistant mutants appear to have a regulatory defect leading to overproduction of one or more endogenous pyrimidine compounds.

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

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Sulfolobus acidocaldarius synthesizes UMP via a standard de novo pathway: results of biochemical-genetic study

Grogan

Gunsalus

1993

J Bacteriol

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“…In strain KD1109 some repression was observed on all the enzymes when cytidine was added, even though the strain was deficient in cytidine (deoxycytidine) deaminase activity. However, it has been shown conclusively that in vivo the cdd mutation does not result in the complete inability to deaminate cytidine (6). Pyrimidine auxotrophs containing a cdd mutation are capable of using cytidine as the sole pyrimidine source unless a second mutation is introduced in the upp (UMP pyrophosphorylase) gene (6).…”

Section: Resultsmentioning

confidence: 99%

“…However, it has been shown conclusively that in vivo the cdd mutation does not result in the complete inability to deaminate cytidine (6). Pyrimidine auxotrophs containing a cdd mutation are capable of using cytidine as the sole pyrimidine source unless a second mutation is introduced in the upp (UMP pyrophosphorylase) gene (6). Thus, with strain KD1109 growing in the presence of cytidine, one is observing the combined repressive effects of (i) added cytidine and (ii) a partial cytidine breakdown to uracil.…”

Section: Resultsmentioning

confidence: 99%

Pyrimidine biosynthetic enzymes of Salmonella typhimurium, repressed specifically by growth in the presence of cytidine

Kelln¹,

Kinahan²,

Foltermann³

et al. 1975

J Bacteriol

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The repressive effects of exogenous cytidine on growing cells was examined in a specially constructed strain in which the pool sizes of endogenous uridine 5'diphosphate and uridine 5'-triphosphate cannot be varied by the addition of uracil and/or uridine to the medium. Five enzymes of the pyrimidine biosynthetic pathway and one enzyme of the arginine biosynthetic pathway were assayed from cells grown under a variety of conditions. Cytidine repressed the synthesis of dihydroorotase (encoded by pyrC), dihydroorotate dehydrogenase (encoded by pyrD), and ornithine transcarbamylase (encoded by argI). Moreover, aspartate transcarbamylase (encoded bypyrB) became further derepressed upon cytidine addition, whereas no change occurred in the levels of the last two enzymes (encoded by pyrE and pyrF) of the pyrimidine pathway. Quantitative nucleotide pool determinations have provided evidence that any individual riboor deoxyribonucleoside mono-, di-, or triphosphate of cytosine or uracil is not a repressing metabolite for the pyrimidine biosynthetic enzymes. Other nucleotide derivatives or ratios must be considered.

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Pyrimidine base and nucleoside metabolism in Pseudomonas cepacia

West

Chu

1987

J. Basic Microbiol.

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Pyrimidine base and nucleoside metabolism in Pseudomonas cepacia was investigated. It was found that this pseudomonad utilized uracil, cytosine or cytidine as a sole nitrogen source while pyrimidine bases and nucleosides supported little bacterial growth as sole carbon sources. Low nucleoside hydrolase and cytosine deaminase activities were detected in P . cepacia. Synthesis of both enzymes appeared to be subject to repression by ammonium ions but repression of cytosine deaminase synthesis was more severe. Synthesis of nucleoside hydrolase or cytosine deaminase was induced if the cells were grown on the substrate cytidine or cytosine, respectively, as a sole nitrogen source.The metabolism of pyrimidine bases and nucleosides has been investigated in few species of the genus Pseudomonas. Unfortunately, pyrimidines were not included in the extensive taxonomic studies concerning the growth of the aerobic pseudomonads upon organic compounds (STANIER et al. 1966, BALLARD et al. 1970).Pyrimidine metabolism has been examined in Pseudomonas acidovorans WARREN 1973, 1974). This pseudoinonad was found to be limited in its utilization of pyrimidine bases and nucleosides due to the absence of a number of salvage pathway enzymes involved in pyrimidine metabolism (KELLN and WARREN 1974). Although pyrimidine biosynthesis has been studied in Pseudomonas aeruginosa and Pseudomonas putida (ISAAC and HOLLOWAY 1968, CONDON et al. 1976), the metabolism of pyrimidines by these microorganisms was not explored with respect to salvage pathways. With relatively little data available about pyrimidine metabolism in pseudomonads, further biochemical characterization of individual species could prove valuable from a taxonomic perspective. The objective of this study was to investigate Pseudomonas cepacia metabolism of pyrimidine bases and nucleosides. This was accomplished by examining its growth on pyrimidine bases and nucleosides as well as by determining which pyrimidine salvage pathway enzymes were present in this pseudomonad.Pseudomonas cepacia ATCC 17759 was utilized in this study (STANIER et al. 1966). The strain was grown in a modified minimal medium of STANIER (1947) that contained 0.1% KH,PO,, 0.1% K,HPO,, 0.1% NaCl, 0.05% sodium citrate -2 H,O, 0.07% MgSO, 7 H,O and 0.4% (NH,),SO,. The medium was adjusted to p H 7.0-7.2 and sterilized. Glucose (0.4%) was added separately as the carbon source. To investigate the ability of P . cepacia to utilize various compounds as sole sources of nitrogen, the strain was grown in liquid minimal medium (5 ml) t h a t lacked (NH,),SO, but contained 0.2% nitrogen source and 0.4% glucose. For sole carbon source determinations, the cells were grown in 5 ml liquid minimal medium (sodinm citrate and glucose omitted) supplemented with 0.2% carbon source and 0.4% (NH,),SO,. Saline-washed cells (approximately lo* cells) were inoculated into liquid medium cultures containing each sole nitrogen or carbon source then the cultures were shaken a t 200 rpm for 8 days a t 30 "C. Optical density a t 600 nm of each...

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Metabolism of Pyrimidines and Pyrimidine Nucleosides by Salmonella typhimurium

Cited by 105 publications

References 26 publications

Sulfolobus acidocaldarius synthesizes UMP via a standard de novo pathway: results of biochemical-genetic study

Sulfolobus acidocaldarius synthesizes UMP via a standard de novo pathway: results of biochemical-genetic study

Pyrimidine biosynthetic enzymes of Salmonella typhimurium, repressed specifically by growth in the presence of cytidine

Pyrimidine base and nucleoside metabolism in Pseudomonas cepacia

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