Gluconate Regulation of Glucose Catabolism in Pseudomonas fluorescens (original) (raw)
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Glucose Uptake and Phosphorylation in Pseudomonas fluorescens
Journal of Bacteriology, 1974
Pseudomonas fluorescens ATCC 13525 and a particulate glucose oxidase ( d -glucose:oxygen oxidoreductase, EC 1.1.3.4) mutant of this organism, gox-7, were examined to determine if glucose oxidation via particulate glucose oxidase is a required first step for glucose uptake. Initial [ 14 C]glucose-uptake rates in parent and gox-7 cells were qualitatively similar. Initial [ 14 C]glucose-uptake product analysis revealed that glucose was accumulated via active transport and was rapidly metabolized to glucose-6-phosphate and gluconate-6-phosphate in both parent and gox-7 cells. Cell extracts contained soluble adenosine 5′-triphosphate specific kinase activity for phosphorylation of glucose. Glucose uptake was induced by glucose and not gluconate, thus, establishing independent regulation of glucose transport and glucose catabolism in p. fluorescens . The results prove that glucose oxidase was not an obligatory reaction for glucose carbon permeation in P. fluorescens . A general unifying s...
Regulation of Glucose Metabolism in Pseudomonas
Journal of Biological Chemistry, 2009
In Pseudomonas putida, genes for the glucose phosphorylative pathway and the Entner-Doudoroff pathway are organized in two operons; one made up of the zwf, pgl, and eda genes and another consisting of the edd, glk, gltR2, and gltS genes. Divergently with ...
Glucose Uptake and Phosphorylation in Pseudomonas fluorescens
Journal of Bacteriology, 1974
Pseudomonas fluorescens ATCC 13525 and a particulate glucose oxidase (D-glucose:oxygen oxidoreductase, EC 1.1.3.4) mutant of this organism, gox-7, were examined to determine if glucose oxidation via particulate glucose oxidase is a required first step for glucose uptake. Initial ["4C]glucose-uptake rates in parent and gox-7 cells were qualitatively similar. Initial ["4C]glucose-uptake
FEMS Microbiology Letters, 2006
Pseudomonas putida CSV86 utilizes glucose, naphthalene, methylnaphthalene, benzyl alcohol and benzoate as the sole source of carbon and energy. Compared with glucose, cells grew faster on aromatic compounds as well as on organic acids. The organism failed to grow on gluconate, 2-ketogluconate, fructose and mannitol. Whole-cell oxygen uptake, enzyme activity and metabolic studies suggest that in strain CSV86 glucose utilization is exclusively by the intracellular phosphorylative pathway, while in Stenotrophomonas maltophilia CSV89 and P. putida KT2442 glucose is metabolized by both direct oxidative and indirect phosphorylative pathways. Cells grown on glucose showed five-to sixfold higher activity of glucose-6-phosphate dehydrogenase compared with cells grown on aromatic compounds or organic acids as the carbon source. Study of [ 14 C]glucose uptake by whole cells indicates that the glucose is taken up by active transport. Metabolic and transport studies clearly demonstrate that glucose metabolism is suppressed when strain CSV86 is grown on aromatic compounds or organic acids.
α-Hydroxyglutarate Oxidoreductase of Pseudomonas putida
Journal of Bacteriology, 1969
Oxidation of D-a-hydroxyglutarate to ct-ketoglutarate is catalyzed by D-ca-hydroxyglutarate oxidoreductase, an inducible membrane-bound enzyme of the electron transport particle [ETP; a comminuted cytoplasmic membrane preparation with enzymic properties and chemical composition resembling beef heart mitochondrial ETP (1)] of Pseudomonas putida P2 (P2-ETP). Treatment of P2-ETP with a nonionic detergent yields a preparation with the sedimentation characteristics of a soluble enzyme, but which retains an intact electron transport chain. Oxygen acts solely as a terminal electron acceptor and may be replaced by ferricyanide, 2,6dichlorophenol indophenol, or mammalian cytochrome c. The oxidoreductase is specific for the D-isomer (Km = 4.0 X 10-4 Mfor DL-a-hydroxyglutarate) and is distinct both from Land D-malate dehydrogenases. Spectral studies suggest that the carrier sequence is substrate-k flavine or nonheme iron-* cyt b-[cyt c]-* oxygen. Our interest in ca-hydroxyglutarate metabolism derived initially from isotope distribution patterns observed during pipecolate and at-aminoadipate oxidation by Pseudomonas putida P2 (Fig. 1). Both pipecolate (13) and a-aminoadipate (R. A. Hartline, Ph.D. Thesis, Univ. of California, San Francisco, 1965) give rise to glutamate, and carbon 6 of a-aminoadipate becomes carbon 5 of glutamate (Hartline, 1965). Although the intermediates between a-ketoadipate and glutamate are not known, it may be inferred that at least one oxidative reaction occurs. Symmetrical intermediates such as glutarate probably are not involved, although asymmetrical glutaryl derivatives such as glutaryl-CoA, glutarate semialdehyde, and a-hydroxyglutarate are likely intermediates. Although a-hydroxyglutarate is a likely intermediate in pipecolate and a-aminoadipate metabolism, attempts to demonstrate its formation have not succeeded (Hartline, 1965). We therefore asked whether an enzyme catalyzing conversion of a-hydroxyglutarate to a-ketoglutarate (reaction 6, Fig. 1) occurred in this organism and whether its synthesis was induced by compounds known to induce formation of enzymes of pipecolate catabolism. This paper reports the properties of Pseudomonas putida ct-hydroxyglutarate oxidoreductase and discusses its possible metabolic role. MATERIALS AND METHODS Chemicals. Materials obtained commercially included: nicotinamide adenine dinucleotide (NAD), nicotinamide adenine dinucleotide phosphate (NADP), hemoglobin (type I, bovine), and horse heart cytochrome c (type II, 67% pure) from Sigma Chemical Co., St. Louis, Mo.; flavine mononucleotide (FMN) and flavine adenine dinucleotide (FAD) from Calbiochem, Los Angeles, Calif.; D-and L-malate, L-glutamate, L-lysine, a-ketoglutarate, pyruvate, oxalacetate, and tris(hydroxymethyl)aminomethane (Tris)-hydrochloride from Nutritional Biochemicals Corp., Cleveland, Ohio; 2,4-dinitrophenylhydrazine and 2, 6-dichlorophenol indophenol from Eastman Organic Chemicals, Rochester, N.Y.; DL-pipecolic acid from Aldrich Chemical Co., Milwaukee, Wisc.;
α-Hydroxyglutarate Oxidoreductase of Pseudomonas putida
Journal of Bacteriology, 1969
Oxidation of D-a-hydroxyglutarate to ct-ketoglutarate is catalyzed by D-ca-hydroxyglutarate oxidoreductase, an inducible membrane-bound enzyme of the electron transport particle [ETP; a comminuted cytoplasmic membrane preparation with enzymic properties and chemical composition resembling beef heart mitochondrial ETP (1)] of Pseudomonas putida P2 (P2-ETP). Treatment of P2-ETP with a nonionic detergent yields a preparation with the sedimentation characteristics of a soluble enzyme, but which retains an intact electron transport chain. Oxygen acts solely as a terminal electron acceptor and may be replaced by ferricyanide, 2,6dichlorophenol indophenol, or mammalian cytochrome c. The oxidoreductase is specific for the D-isomer (Km = 4.0 X 10-4 Mfor DL-a-hydroxyglutarate) and is distinct both from L-and D-malate dehydrogenases. Spectral studies suggest that the carrier sequence is substrate -k flavine or nonheme iron -* cyt b --[cyt c] -* oxygen.
Most phosphate-solubilizing bacteria (PSB), including the Pseudomonas species, release P from sparingly soluble mineral phosphates by producing high levels of gluconic acid from extracellular glucose, in a reaction catalyzed by periplasmic glucose dehydrogenase, which is an integral component of glucose catabolism of pseudomonads. To investigate the differences in the glucose metabolism of gluconic acid-producing PSB pseudomonads and low gluconic acid-producing/non-PSB strains, several parameters pertaining to growth and glucose utilization under P-sufficient and P-deficient conditions were monitored for the PSB isolate Pseudomonas aeruginosa P4 (producing w46 mM gluconic acid releasing 437 mM P) and non-PSB P. fluorescens 13525. Our results show interesting differences in the channeling of glucose towards gluconate and other catabolic end-products like pyruvate and acetate with respect to P status for both strains. However, PSB strain P. aeruginosa P4, apart from exhibiting better growth under both low and high Pi conditions, differed from P. fluorescens 13525 in its ability to accumulate gluconate under P-solubilizing conditions. These alterations in growth, glucose utilization and acid secretion are correlated with glucose dehydrogenase, glucose-6-phosphate dehydrogenase and pyruvate carboxylase activities. The ability to shift glucose towards a direct oxidative pathway under P deficiency is speculated to underlie the differential gluconic acid-mediated P-solubilizing ability observed amongst pseudomonads.
PLoS ONE, 2013
Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ), and two genes (sup5 and sup6) which seem to be organized in a putative operon. This operon (named supX) consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.