Pyrimidine metabolism in <i>Pseudomonas acidovorans</i>

Kelln, Rod A.; Warren, R. A. J.

doi:10.1139/m74-067

Cited by 16 publications

(9 citation statements)

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“…Various members of the genus Pseudomonas are able to grow on purines either as a nitrogen source or as a nitrogen and carbon source. Adenine, guanine, hypoxanthine, and xanthine serve as nitrogen sources for P. aeruginosa (170,433), P. acidovorans (263), and an unidentified pseudomonad (139), and these purines are used also as sole carbon and nitrogen sources by P. acidovorans (478) and other pseudomonads (20,90). Adenine inhibits the growth of some strains ofP.…”

Section: Bacteriamentioning

confidence: 99%

Degradation of purines and pyrimidines by microorganisms.

Vogels¹,

Drift²

1976

Bacteriological Reviews

373

192

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Section: Bacteriamentioning

confidence: 99%

Degradation of purines and pyrimidines by microorganisms.

Vogels¹,

Drift²

1976

Bacteriological Reviews

373

192

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“…cepacia is compared to that observed for P . acidovorans (KELLN and WARREN 1974), some similarities between these species become evident. With respect to nitrogen sources, the pyrimidine bases uracil and cytosine supported the growth of both pseudomonads.…”

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confidence: 89%

“…With respect to nitrogen sources, the pyrimidine bases uracil and cytosine supported the growth of both pseudomonads. Also, both microorganisms have been reported to contain cytosine deaminase as well as lack cytidine deaminase, uridine phosphorylase and thymidine phosphorylase (KELLN and WARREN 1974).…”

mentioning

confidence: 99%

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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“…Regulatory mutations increasing pyrD expression S. typhimurium mutants showing increased expression of pyrD in repressing growth conditions were obtained by employing a stable p y r D : : Mud1 (Ap'lac) fusion strain, mutagenizing with ethyl methanesulfonate and basing selection on lactose utilization [18]. The pyrD leader regions of three mutants, KP1983 (pyrD '5), KP1984 (pyrD'20) and KP1990 (pyrD'7) were cloned and sequenced.…”

Section: Dna Sequence Of the Pyrd Genementioning

confidence: 99%

Cloning, nucleotide sequence and regulation of the Salmonella typhimurium pyrD gene encoding dihydroorotate dehydrogenase

Frick

Neuhard²,

Kelln

1990

European Journal of Biochemistry

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The Salmonella typhimurium pyrD gene encoding dihydroorotate dehydrogenase was cloned and sequenced. In total, a sequence of 1286 nucleotide pairs was determined wherein a single open-reading-frame of 1011 bp, encoding a polypeptide of 336 amino acids having 95% similarity with the Escherichia coli pyrD gene product, was identified. A region of hyphenated-dyad symmetry exists within the leader region affording the potential for the formation of a stable secondary structure in the 5' end of the transcript. Mutations from several regulatory mutants were located within the region of dyad symmetry which would impart changes in the transcript within the putative secondary structure, implicating the secondary structure in regulation. Primer extension analysis revealed multiple transcriptional start sites located six to nine nucleotides downstream from the Pribnow box, with the primary initiation site differing in repressing and derepressing growth conditions. The results are discussed in terms of a translational attenuation model for regulation of pyrD expression.In Salmonella typhimurium and Escherichia coli, the pyrD gene encodes dihydroorotate dehydrogenase, the fourth enzyme of the pyrimidine biosynthetic pathway. The enzyme is membrane-bound [l] and linked to the electron transport system of the cell [2]. The E. coli enzyme has been purified and shown to consist of two identical flavin-containing subunits [3, 41. The synthesis of dihydroorotate dehydrogenase is regulated in a complex manner by the intracellular nucleotide pools, being negatively correlated with the concentration of CTP [5, 61 and Each mutation would decrease the stability of the putative secondary structure in the transcript, suggesting that pyrC expression is controlled at the level of translational initiation. A similar involvement of the symmetry regions of the E. coli pyrD and pyrC genes has yet to be demonstrated.To gain further insight into the regulation of pyrD expression in S. typhimuriurn, the gene has been cloned and sequenced. Regulatory mutants overexpressing pyrD have been isolated and the mutations identified. Additionally, the transcriptional start sites in repressing and derepressing conditions have been determined. MATERIALS AND METHODS Bacterial strains, bacteriophages and plasmid vectorsplasmid vectors employed, are listed in Table 1.The S. typhimuriurn LT2 and E. coli K12 strains, and the Media and growth conditionsThe composition of the minimal medium [5] and LB medium [20] has been reported. Glucose and casamino acids were added to minimal medium at 0.2%. Other supplements were added at the following final concentrations: ampicillin (50 pg/ ml) ; tetracycline (10 pg/ml) ; 5-bromo-4-chloro-3-indolyl-~-~-galactopyranoside (40 pg/ml); cytidine (50 pg/ml) ; uracil Regulation was studied in KP1725 which has a mutant pyrH gene encoding a partially defective UMP kinase, and when grown in the absence of exogenous pyrimidines is partially starved for pyrimidine nucleotides. Addition of cytidine and uracil results in swelling of ...

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Pyrimidine metabolism in Pseudomonas acidovorans

Cited by 16 publications

References 0 publications

Degradation of purines and pyrimidines by microorganisms.

Degradation of purines and pyrimidines by microorganisms.

Pyrimidine base and nucleoside metabolism in Pseudomonas cepacia

Cloning, nucleotide sequence and regulation of the Salmonella typhimurium pyrD gene encoding dihydroorotate dehydrogenase

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