Glucose Uptake and Phosphorylation 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...
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.
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 ...
Archives of Microbiology, 1997
Oxygen uptake and glucose and glutamate oxidation kinetics of the heterotrophic bacterium Pseudomonas chlororaphis grown in glucose-or glutamate-limited cultures under oxygen-saturating or oxygen-limiting conditions were determined. K m values for oxygen were 1.4-5.6 µM. Only in the case of glucose were significantly lower K m values and enhanced specific oxygen affinity (V max /K m) per cell found under oxygen-limiting conditions. Both K m and specific affinity values for glucose and glutamate oxidation were apparently affected by oxygen concentration, although a statistically significant enhancement of the oxidation kinetics was found only for glutamate. The kinetic data found for P. chlororaphis support the conclusion that the outcome of competition for oxygen with Nitrosomonas europaea in the rhizosphere of oxygen-releasing macrophytes will primarily be determined by oxidation kinetics of the electron donor instead of the oxygen uptake kinetics of the respective organisms.
Respiration of Pseudomonas fluorescens as a function of intracellular substrate concentration
1997
Abstract A kinetic method to measure the intracellular concentration of respiratory substrates in short-term starvation-enrichment experiments is proposed. Samples of bacterial suspension from steady-state chemostat cultures were subjected to 25 min starvation, followed by pulse addition of [14 C] glucose. Residual substrate utilization rates and respiration rates (uptake of dissolved O 2) before and after amendment were recorded.
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.
Gluconate Regulation of Glucose Catabolism in Pseudomonas fluorescens
Journal of Bacteriology, 1972
Induction of Entner-Doudoroff pathway enzymes in Pseudomonas fluorescens was investigated to study the role of gluconate as a possible inducer. Glucose oxidase-deficient mutants were isolated and characterized. One of these mutants, gox-7, was deficient in particulate glucose oxidase; another mutant, gox-17, was deficient in particulate glucose and gluconate oxidase activities. Gluconate, but not glucose, induced synthesis of gluconokinase and 6-phosphogluconate dehydratase in both mutants. High constitutive levels of 2-keto-3-deoxy-6-phosphogluconate aldolase were found when both mutants were grown on glucose. Growth of parent and both mutant strains on glycerol also resulted in high levels of Entner-Doudoroff pathway enzymes. It was concluded that glucose cannot serve as an inducer molecule for derepression of Entner-Doudoroff pathway enzymes in P. fluorescens. Evidence presented provides good support for gluconate being the true inducer of this pathway in P. fluorescens. A relationship is presented for explaining distribution of the Entner-Doudoroff pathway in certain groups of bacteria. ' Presented in part at the 71st Annual Meeting of the American Society for Microbiology, Minneapolis, Minn., 2-7 May 1971. 2This work is part of a dissertation submitted by the senior author in partial fulfillment of requirements for the B.A. degree, Honors College, Western Michigan University.