scholarly journals The regulation of transport of glucose and methyl α-glucoside in Pseudomonas aeruginosa

1973 ◽  
Vol 132 (2) ◽  
pp. 141-154 ◽  
Author(s):  
M. Midgley ◽  
E. A. Dawes
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Energy Dependence ◽  
Transport System ◽  
Glucose Dehydrogenase ◽  
The Other ◽  
Citrate Metabolism ◽  
Glucose Transport System ◽  
Regulation Of Transport ◽  
Extracellular Activity ◽  
By Products

The methyl α-glucoside-transport system of Pseudomonas aeruginosa has been characterized with respect to its specificity, energy-dependence, kinetics and regulation. The uptake of glucose involved two components, one of which transported glucose (Km=8μm) and methyl α-glucoside (Km=2.8mm) whereas the other was more complex, involving the extracellular activity of glucose dehydrogenase. Mutants defective in this enzyme have been isolated and characterized. The methyl α-glucoside–glucose-transport system was repressed when the organism was grown in the absence of glucose; the induction of this transport system by glucose, and its activity once induced, were inhibited by products of citrate metabolism.

scholarly journals The regulation of transport of glucose, gluconate and 2-oxogluconate and of glucose catabolism in Pseudomonas aeruginosa

1976 ◽  
Vol 154 (3) ◽  
pp. 659-668 ◽  
Author(s):  
P H. Whiting ◽  
M Midgley ◽  
E A. Dawes
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glucose Transport ◽  
Transport System ◽  
Glucose Concentration ◽  
Glucose Dehydrogenase ◽  
Threshold Concentration ◽  
Transport Systems ◽  
Residual Concentration ◽  
Catabolic Enzymes ◽  
Glucose Transport System

1. The induction by glucose and gluconate of the transport systems and catabolic enzymes for glucose, gluconate and 2-oxogluconate was studied with Pseudomonas aeruginosa PAO1 growing in a chemostat under conditions of nitrogen limitation with citrate as the major carbon source. 2. In the presence of a residual concentration of 30mM-citrate an inflowing glucose concentration of 6-8 mM was required to induce the glucose-transport system and associated catabolic enzymes. When the glucose concentration was raised to 20mM the glucose-transport system was repressed, but the transport system for gluconate, and at higher glucose concentrations, that for 2-oxogluconate, were induced. No repression of the glucose-catabolizing enzymes occurred at the higher inflowing glucose concentrations. 3. In the presence of 30mM-citrate no marked threshold concentration was required for the induction of the gluconate-transport system by added gluconate. 4. In the presence of 30mM-citrate and various concentrations of added glucose and gluconate, the activity of the glucose-transport system accorded with the proposal that a major factor concerned in the repression of this system was the concentration of gluconate, produced extracellularly by glucose dehydrogenase. 5. This proposal was supported by chemostat experiments with mutants defective in glucose dehydrogenase. Such mutants showed no repression of the glucose-transport system by high inflowing concentrations, but with a mutant apparently defective only in glucose dehydrogenase, the addition of gluconate caused repression of the glucose-transport system. 6. Studies with the mutants showed that both glucose and gluconate can induce the enzymes of the Entner-Doudoroff system, whereas for the induction of the gluconate-transport system glucose must be converted into gluconate.

Substrate specificity of the high-affinity glucose transport system of Pseudomonas aeruginosa

1993 ◽  
Vol 39 (7) ◽  
pp. 722-725 ◽  
Author(s):  
John L. Wylie ◽  
Elizabeth A. Worobec
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glucose Transport ◽  
Transport System ◽  
Binding Protein ◽  
High Affinity ◽  
Glucose Binding ◽  
Glucose Transport System ◽  
Glucose Binding Protein

Specificity of the high-affinity glucose transport system of Pseudomonas aeruginosa was examined. At a concentration of [14C]glucose near the Vmax of the system, inhibition by maltose, galactose, and xylose was detected. This inhibition is similar to that detected in earlier in vivo studies and correlates with the known specificity of OprB, a glucose-specific porin of P. aeruginosa. At a level of [14C]glucose 100 times lower, only unlabelled glucose inhibited uptake to any extent. This matches the known in vitro specificity of the periplasmic glucose binding protein. These findings were used to explain the discrepancy between earlier in vivo and in vitro results reported in the literature.Key words: Pseudomonas aeruginosa, glucose transport, OprB, glucose binding protein.

Hyperpolarization as a mediator of insulin action: increased muscle glucose uptake induced electrically

1980 ◽  
Vol 239 (1) ◽  
pp. E21-E29 ◽  
Author(s):  
K. Zierler ◽  
E. M. Rogus
Keyword(s):  
Glucose Uptake ◽  
Glucose Transport ◽  
Transport System ◽  
Continuous Flow ◽  
Insulin Action ◽  
Interstitial Fluid ◽  
The Other ◽  
Glucose Transport System ◽  
Sucrose Gap ◽  
Whole Muscle

Insulin hyperpolarizes. This raises the questions: is hyperpolarization a means by which insulin exerts some of its other effects, and can electrically induced hyperpolarization mimic insulin action on membrane functions? A technique was devised to study the latter question. The technique permits electrical hyperpolarization of a segment of whole muscle. Rat caudofemoralis muscle was threaded into a triple sucrose-gap chamber. Continuous flow of sucrose displaced interstitial fluid of muscle segments in the gaps. In one electrolyte compartment between gaps was placed an anode and in the other a cathode. The muscle segment in the anodal compartment was hyperpolarized continuously for 30 min, probably by about 1.5 mV. Uptake of deoxyglucose was increased in the hyperpolarized muscle segment. This increase, by 39%, was highly significant. It was probably smaller than the twofold increase elicited by insulin (100 mU/ml), but not than the possible effect produced by 10 mU/ml. The effect of hyperpolarization was specific for the D-glucose transport system because uptake of L-glucose was not altered.

2-Deoxyglucose Transportation Via Passive Diffusion and its Oxidation, Not Phosphorylation to 2-Deoxygluconic Acid by Pseudomonas aeruginosa

1971 ◽  
Vol 49 (5) ◽  
pp. 606-613 ◽  
Author(s):  
R. G. Eagon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Active Transport ◽  
Transport System ◽  
Glucose Dehydrogenase ◽  
Passive Diffusion ◽  
Suggestive Evidence ◽  
System 2 ◽  
Membrane Bound ◽  
Active Transport System ◽  
Oxidation Of Glucose

The transport and catabolism of 2-deoxyglucose by Pseudomonas aeruginosa were studied. 2-Deoxyglucose was taken up and oxidized by glucose-grown cells at a rate approaching that of the uptake and oxidation of glucose. However, 2-deoxyglucose entered these cells via passive diffusion while glucose entered via an inducible active transport system. 2-Deoxyglucose was oxidized stoichiometrically, presumably by glucose dehydrogenase, to 2-deoxygluconic acid which, in turn, diffused out of the cells. No phosphorylated intermediates were detected. Glucose dehydrogenase was induced by cultivating the cells on glucose. There was suggestive evidence that the membrane-bound glucose dehydrogenase provided energy for the transport of glucose.

scholarly journals The uptake of 2-deoxy-d-glucose by Pseudomonas aeruginosa and its regulation

1973 ◽  
Vol 132 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Antony J. Mukkada ◽  
George L. Long ◽  
Antonio H. Romano
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Organic Acids ◽  
Glucose Transport ◽  
Transport System ◽  
Citric Acid Cycle ◽  
Glucose Repression ◽  
Carrier System ◽  
Glucose Transport System ◽  
Unchanged Form ◽  
Glucose Analogue

The non-metabolizable glucose analogue 2-deoxy-d-glucose is taken up by Pseudomonas aeruginosa against a concentration gradient, in a predominantly unchanged form. d-Glucose competitively inhibits 2-deoxy-d-glucose uptake and also causes a rapid exit of intracellular 2-deoxy-d-glucose. Thus these two sugars share the same stereospecific carrier system, and glucose transport can be studied reliably with 2-deoxy-d-glucose. The transport system is inducible, and is strongly repressed by a number of organic acids such as acetate, citrate, succinate, fumarate and malate, even in the presence of adequate excess of the inducer (d-glucose). Repression by organic acids can be relieved by transferring cells to a glucose medium, but in the presence of chloramphenicol the cells fail to recover from repression, indicating that the formation of the transport system involves the synthesis of protein. The results demonstrate that the regulation of glucose metabolism effected by citric acid-cycle intermediates in P. aeruginosa is manifest at the level of the glucose-transport system.

Temporal variability of disinfection by-products concentration in urban public water system

2013 ◽  
Vol 14 (4) ◽  
pp. 393-398
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Temporal Variability ◽  
Water System ◽  
The Other ◽  
Major Constituent ◽  
System P ◽  
Public Water System ◽  
Drinking Water Samples ◽  
By Products

The occurrence of trihalomethanes (THMs) was studied in the drinking water samples from urban water supply network of Karachi city that served more than 18 million people. Drinking water samples were collected from 58 locations in summer (May-August) and winter (November-February) seasons. The major constituent of THMs detected was chloroform in winter (92.34%) and summer (93.07%), while the other THMs determined at lower concentrations. Summer and winter concentrations of total THMs at places exceed the levels regulated by UEPA (80 μg l-1) and WHO (100 μg l-1). GIS linked temporal variability in two seasons showed significantly higher median concentration (2.5%-23.06%) of THMs compared to winter.

Biodegradation of chlorophenols by immobilized pure-culture microorganisms

1996 ◽  
Vol 34 (10) ◽  
pp. 67-72 ◽  
Author(s):  
Lu Chih-Jen ◽  
Lee Chi-Mei ◽  
Huang Chiou-Zong
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Putida ◽  
Pure Culture ◽  
The Other ◽  
Batch Reactors ◽  
Agrobacterium Radiobacter ◽  
Culture Cells ◽  
Lag Period

The biodegradation of phenol and chlorophenols by immobilized pure-culture cells was conducted by a series of batch reactors. The microorganisms used in this study were Pseudomonas putida, Psuedomonas testosteroni, Pseudomonas aeruginosa, and Agrobacterium radiobacter. All four species showed the ortho-cleavage pathway to metabolize chlorophenols. Among the four species, P. testosteroni, P. putida, and P. aeruginosa could effectively remove phenol at 200 mg/l. P. testosteroni could effectively remove 2-chlorophenol at 10mg/l. However, the other three species, P. putida, P. aeruginosa, and A. radiobacter, could not effectively remove 2-chlorophenol. Although 3-chlorophenol is a recalcitrant compound, P. testosteroni also could rapidly metabolize 3-chlorophenol at 10 mg/l. The removal of 4-chlorophenol at 10 mg/l by P. testosteroni reached 98% within one day. P. aeruginosa and A. radiobacter also could metabolize 4-chlorophenol after 2 and 7 days of lag period, respectively.

Modulation of glucose transport by parathyroid hormone and insulin in UMR 106–01, a clonal rat osteogenic sarcoma cell line

1995 ◽  
Vol 14 (2) ◽  
pp. 263-275 ◽  
Author(s):  
D M Thomas ◽  
S D Rogers ◽  
M W Sleeman ◽  
G M Pasquini ◽  
F R Bringhurst ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Cell Line ◽  
Glucose Transport ◽  
Transport System ◽  
Osteogenic Sarcoma ◽  
Regulatory Subunit ◽  
Sarcoma Cell ◽  
Sarcoma Cell Line ◽  
Glucose Transport System ◽  
Umr 106

ABSTRACT This study characterizes the actions of insulin and parathyroid hormone (PTH) on the glucose transport system in the rat osteogenic sarcoma cell line UMR 106–01, which expresses a number of features of the osteoblast phenotype. Using [1,2-3H]2-deoxyglucose (2-DOG) as a label, UMR 106–01 cells were shown to possess a glucose transport system which was enhanced by insulin. In contrast, PTH influenced glucose transport in a biphasic manner with a stimulatory effect at 1 h and a more potent inhibitory effect at 16 h on basal and insulin-stimulated 2-DOG transport. To explore the mechanism of PTH action, a direct agonist of cAMP-dependent protein kinase (PKA) was tested. 8-Bromo-cAMP had no acute stimulatory effect but inhibited basal and insulin-stimulated 2-DOG transport at 16 h. This result suggested that the prolonged, but not the acute, effect of PTH was mediated by the generation of cAMP. Further studies with the cell line UMR 4–7, a UMR 106–01 clone stably transfected with an inducible mutant inactive regulatory subunit of PKA, confirmed that the inhibitory but not the stimulatory effect of PTH was mediated by the PKA pathway. Northern blot data indicated that the prolonged inhibitory effects of PTH and 8-bromo-cAMP on glucose transport were likely to be mediated in part by reduction in the levels of GLUT1 (HepG2/brain glucose transporter) mRNA.

scholarly journals Polyphenol Profiling of Chestnut Pericarp, Integument and Curing Water Extracts to Qualify These Food By-Products as a Source of Antioxidants

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2335
Author(s):  
Gabriella Pinto ◽  
Sabrina De Pascale ◽  
Maria Aponte ◽  
Andrea Scaloni ◽  
Francesco Addeo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Negative Impact ◽  
Tap Water ◽  
Time Of Flight ◽  
The Other ◽  
Curing Process ◽  
Flight Mass Spectrometry ◽  
Water Curing ◽  
The Impact ◽  
By Products

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6–7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut’s appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.

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