Glucose transport by an arctic and a temperate strain of rhizobia

1991 ◽  
Vol 37 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Pierre C. Bigwaneza ◽  
Danielle Prévost ◽  
Lucien M. Bordeleau ◽  
Hani Antoun
Keyword(s):  
Key Words ◽  
Glucose Transport ◽  
Transport System ◽  
High Energy ◽  
The Arctic ◽  
Transport Systems ◽  
High Energy Phosphate ◽  
Rhizobium Species ◽  
Onobrychis Viciifolia ◽  
Active Mechanism

Glucose transport was studied in two strains of Rhizobium species effective on sainfoin (Onobrychis viciifolia), the arctic strain N31 isolated from Astragalus alpinus and the temperate strain SM2 isolated from sainfoin. The two strains had comparable glucose transport systems with a biphasic kinetics, indicating the presence of a high- and low-affinity transport system. Apparent Km and Vmax values for the high- and low-affinity transport systems were, respectively, 4.7 and 53.4 μM and 12.7 and 58.9 nmol∙min−1∙mg protein−1 with N31 and 2.6 and 72.6 μM and 10.1 and 64.6 nmol∙min−1∙mg protein−1 with SM2. Glucose transport systems were inhibited by 2,4-dinitrophenol, KCN, azide, and N-ethylmaleimide. NaF did not affect glucose transport, while arsenate showed partial inhibition of the low-affinity transport system with strain N31. These results suggest an active mechanism of transport that is dependent on an energized membrane but does not directly utilize high-energy phosphate compounds. In the two strains, glucose transport is constitutive and repressed by succinate, and it is glucose specific. Key words: Arctic, glucose, Rhizobium, symbiosis, transport.

Effect of temperature on succinate transport by an arctic and a temperate strain of rhizobia

1993 ◽  
Vol 39 (10) ◽  
pp. 907-911 ◽  
Author(s):  
Pierre C. Bigwaneza ◽  
Danielle Prévost ◽  
Lucien M. Bordeleau ◽  
Hani Antoun
Keyword(s):  
Transport System ◽  
Cold Adaptation ◽  
Proton Motive Force ◽  
The Arctic ◽  
Transport Systems ◽  
Effect Of Temperature ◽  
Rhizobium Strain ◽  
Onobrychis Viciifolia ◽  
Carbonyl Cyanide ◽  
Similar Kinetic

The effect of temperature on the succinate transport system was studied in the arctic Rhizobium strain N31 (isolated from Astragalus alpinus) and in the temperate strain SM2 (isolated from Onobrychis viciifolia). Only one inducible succinate transport system was found in the two strains as indicated by the linear Eadie–Hofstee plot obtained at 10, 15, and 25 °C. The transport of succinate was not affected by arsenate, but was inhibited by carbonyl cyanide m-chlorophenylhydrazone, KCN, and iodoacetate, implying an active process, a proton motive force, and essential sulfhydryl groups in the system. At 25 °C the apparent Km and Vmax values observed were 6.7 and 7.4 μM and 40.8 and 27.9 nmol∙min−1∙mg protein−1 for strains N31 and SM2, respectively. Similar kinetic parameters for succinate transport at 25 °C were obtained with the cells of both strains grown at 10 or 25 °C. However, when transport was measured at 10 °C the Km and Vmax values obtained with strain SM2 were higher for cells cultured at 10 °C than for those cultured at 25 °C, suggesting that this temperate strain might be more affected by low growth temperature than the arctic strain N31. The succinate transport systems in the two strains were affected by temperature in a similar fashion, as indicated by similar Arrhenius plots of Vmax showing a discontinuity at 20 °C and by comparable apparent energy of activation values. These observations suggest that the cold adaptation of strain N31 is not related to a cold adaptation of the succinate carrier.Key words: arctic, Rhizobium, succinate, symbiosis, transport.

scholarly journals Renal transport of neutral amino acids. Tubular localization of Na+-dependent phenylalanine- and glucose-transport systems

1984 ◽  
Vol 220 (1) ◽  
pp. 15-24 ◽  
Author(s):  
U Kragh-Hansen ◽  
H Røigaard-Petersen ◽  
C Jacobsen ◽  
M I Sheikh
Keyword(s):  
Glucose Transport ◽  
Transport System ◽  
Membrane Vesicles ◽  
Transport Systems ◽  
Rabbit Kidney ◽  
Outer Cortex ◽  
High Affinity ◽  
Pars Recta ◽  
Pars Convoluta ◽  
Phenylalanine Transport

The transport properties for phenylalanine and glucose in luminal-membrane vesicles from outer cortex (pars convoluta) and outer medulla (pars recta) of rabbit kidney were studied by a spectrophotometric method. Uptake of phenylalanine as well as of glucose by the two types of membrane vesicles was found to be Na+-dependent, electrogenic and stereospecific. Na+-dependent transport of L-phenylalanine by outer-cortical membrane vesicles could be accounted for by one transport system (KA congruent to 1.5 mM). By contrast, in the outer-medullary preparation, L-phenylalanine transport occurred via two transport systems, namely a high-affinity system with K1A congruent to 0.33 mM and a low-affinity system with K2A congruent to 7 mM respectively. Na+-dependent uptake of D-glucose by pars convoluta and pars recta membrane vesicles could be described by single, but different, transport systems, namely a low-affinity system with KA congruent to 3.5 mM and a high-affinity system with KA congruent to 0.30 mM respectively. Attempts to calculate the stoichiometry of the different Na+/D-glucose transport systems by using Hill-type plots revealed that the ratio of the Na+/hexose co-transport probably is 1:1 in the case of pars convoluta and 2:1 in membrane vesicles from pars recta. The Na+/L-phenylalanine stoichiometry of the pars convoluta transporter probably is 1:1. Both the high-affinity and the low-affinity Na+-dependent L-phenylalanine transport system of pars recta membrane vesicles seem to operate with a 1:1 stoichiometry. The physiological importance of the arrangement of low-affinity and high-affinity transport systems along the kidney proximal tubule is discussed.

scholarly journals Role of Periplasmic Trehalase in Uptake of Trehalose by the Thermophilic Bacterium Rhodothermus marinus

2008 ◽  
Vol 190 (6) ◽  
pp. 1871-1878
Author(s):  
Carla D. Jorge ◽  
Luís L. Fonseca ◽  
Winfried Boos ◽  
Helena Santos
Keyword(s):  
Kinetic Parameters ◽  
Glucose Transport ◽  
Transport System ◽  
Glucose Transporter ◽  
Thermophilic Bacterium ◽  
Transport Systems ◽  
Uptake System ◽  
Rhodothermus Marinus ◽  
Whole Cells ◽  
Physiological Relevance

ABSTRACT Trehalose uptake at 65°C in Rhodothermus marinus was characterized. The profile of trehalose uptake as a function of concentration showed two distinct types of saturation kinetics, and the analysis of the data was complicated by the activity of a periplasmic trehalase. The kinetic parameters of this enzyme determined in whole cells were as follows: Km = 156 ± 11 μM and V max = 21.2 ± 0.4 nmol/min/mg of total protein. Therefore, trehalose could be acted upon by this periplasmic activity, yielding glucose that subsequently entered the cell via the glucose uptake system, which was also characterized. To distinguish the several contributions in this intricate system, a mathematical model was developed that took into account the experimental kinetic parameters for trehalase, trehalose transport, glucose transport, competition data with trehalose, glucose, and palatinose, and measurements of glucose diffusion out of the periplasm. It was concluded that R. marinus has distinct transport systems for trehalose and glucose; moreover, the experimental data fit perfectly with a model considering a high-affinity, low-capacity transport system for trehalose (Km = 0.11 ± 0.03 μM and V max = 0.39 ± 0.02 nmol/min/mg of protein) and a glucose transporter with moderate affinity and capacity (Km = 46 ± 3 μM and V max = 48 ± 1 nmol/min/mg of protein). The contribution of the trehalose transporter is important only in trehalose-poor environments (trehalose concentrations up to 6 μM); at higher concentrations trehalose is assimilated primarily via trehalase and the glucose transport system. Trehalose uptake was constitutive, but the activity decreased 60% in response to osmotic stress. The nature of the trehalose transporter and the physiological relevance of these findings are discussed.

Uptake of D-glucose and L-proline by oligotrophic and heterotrophic marine bacteria

1980 ◽  
Vol 26 (4) ◽  
pp. 454-459 ◽  
Author(s):  
Y. Akagi ◽  
N. Taga
Keyword(s):  
Glucose Transport ◽  
Transport System ◽  
Marine Bacteria ◽  
Heterotrophic Bacterium ◽  
Kinetic Studies ◽  
Transport Systems ◽  
Proline Transport ◽  
Oligotrophic Bacterium ◽  
Glucose Transport System ◽  
Broad Specificity

The transport systems of the oligotrophic bacterium 486 for D-glucose and L-proline have been compared with those of the heterotrophic bacterium RP-303. Kinetic studies demonstrated that the rates of D-glucose and L-proline uptake by the two organisms were saturable processes. The apparent Km values of strain 486 for D-glucose and L-proline were 13.0 μM and 0.2 μM, respectively, whereas those of strain RP-303 were 3.2 μM for D-glucose and 1.8 μM for L-proline. Competition studies indicated that the D-glucose transport system of each bacterium was highly specific for D-glucose. The L-proline transport system of the oligotrophic bacterium 486 had a broad specificity, whereas that of the heterotrophic bacterium RP-303 had a narrow one.

Renal sugar transport in the winter flounder. III. Two glucose transport systems

1977 ◽  
Vol 232 (3) ◽  
pp. F227-F234 ◽  
Author(s):  
A. Kleinzeller ◽  
G. R. Dubyak ◽  
P. M. Griffin ◽  
E. M. McAvoy ◽  
J. M. Mullin ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Glucose Transport ◽  
Transport System ◽  
Sugar Transport ◽  
Winter Flounder ◽  
Transport Systems ◽  
Renal Tubules ◽  
Pyranose Ring ◽  
Structural Requirements ◽  
Specificity Pattern

Teased renal tubules of the winter flounder (Pseudopleuronectes americanus) were employed to investigate the structural requirements for two pathways of D-glucose transport which take place preponderantly across the basal (antiluminal) face of renal cells. 1) An inhibition analysis of the equilibrating, Na-independent and phlorizin-sensitive transport of the nonmetabolizable methyl-alpha-D-glucoside (0.1 and 0.5 mM), with 20 glucose analogs (5 mM), was employed to establish the structural requirements for the substrate-carrier interaction: a (pyranose) ring, oxygen, or F at C1, C2-OH, C3-OH, and C4-OH (all axial, 1C model). Some interaction may also occur at C6-OH. D-Glucose shares this transport system. Hydrogen bonding between the oxygens and the carrier is suggested. 2) The phloretin- and phlorizin-sensitive, ouabain-insensitive transport of D-glucose, 2-deoxy-D-glucose, and D-mannose is associated with considerable phosphorylation. The three sugars mutually compete for a shared transport site. The specificity pattern characterizing the transport system defines the following structural requirements: a (pyranose) ring, a free C1-OH, C3-OH, and C4-OH (both axial) and possibly C6-OH. Hydrogen bonding between the carrier and the oxygens at C3, C4, and C6, and covalent bonding at C1 is suggested.

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.

scholarly journals Testing transport models and transport data by means of kinetic rejection criteria

1989 ◽  
Vol 260 (3) ◽  
pp. 885-891 ◽  
Author(s):  
R M Krupka
Keyword(s):  
Experimental Data ◽  
Kinetic Analysis ◽  
Glucose Transport ◽  
Transport System ◽  
Reaction Scheme ◽  
Transport Systems ◽  
Choline Transport ◽  
Carrier Model ◽  
Glucose Transport System ◽  
General Relations

In the case of a transport system obeying Michaelis-Menten kinetics, completely general relationships are shown to exist between the final ratio of internal and external substrate concentrations, alpha, and the V/Km ratios found in zero-trans-entry, zero-trans-exit and equilibrium-exchange experiments (where V is a maximum substrate flux and Km a substrate half-saturation constant). The proof depends on a new method of derivation proceeding from the form of the experimental data rather than, as has been the practice in kinetic analysis, from a hypothetical reaction scheme. These general relationships, which will be true of all mechanisms giving rise to a particular type of behaviour (here Michaelis-Menten kinetics), provide a test for internal consistency in a set of experimental data. Other relationships, which are specific, can be derived from individual reaction schemes, with the use of traditional procedures in kinetic analysis. The specific relationships include constants for infinite trans entry and exit in addition to constants involved in the general relationships. In conjunction, the general and specific relationships provide a stringent test of mechanism. A set of results that fails to satisfy the general relationships must be rejected; here systematic error or unexpected changes in the transport system in different experiments may have distorted the calculated constants, or the system may not actually obey Michaelis-Menten kinetics. Results in accord with the general relationships, on the other hand, can be applied in specific tests of mechanism. The usefulness of the theorem is illustrated in the cases of the glucose-transport and choline-transport systems of erythrocytes. Experimental results taken from several studies in the literature, which were in accord with hyperbolic substrate kinetics, had previously been shown to disagree with relationships derived for the carrier model, and the model was rejected. The new analysis shows that the data violated the general relationships and therefore cannot decide the issue. More recent results on the glucose-transport system satisfy the general relations and agree with the carrier model.

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