Adenine nucleotide contents and energy charge of Azotobacter vinelandii grown at low phosphate concentration

1987 ◽  
Vol 147 (4) ◽  
pp. 354-357 ◽  
Author(s):  
T. de la Rubia ◽  
J. Gonzalez-Lopez ◽  
J. Moreno ◽  
M. V. Martinez-Toledo ◽  
A. Ramos-Cormenzana
Keyword(s):  
Azotobacter Vinelandii ◽  
Adenine Nucleotide ◽  
Energy Charge ◽  
Phosphate Concentration

Effects of oxygen and nitrate on ammonium uptake kinetics and adenylate pools in Phalaris arundinacea L. and Glyceria maxima (Hartm.) Holmb

1994 ◽  
Vol 102 ◽  
pp. 333-342 ◽  
Author(s):  
H. Brix ◽  
B. Lorenzen ◽  
J. T. Morris ◽  
H.-H. Schierup ◽  
B. K. Sorrell
Keyword(s):  
Adenine Nucleotide ◽  
Block Design ◽  
Energy Charge ◽  
Estimation Procedure ◽  
Dry Weight ◽  
Phalaris Arundinacea ◽  
Uptake Kinetics ◽  
Charge Ratio ◽  
Ammonium Uptake ◽  
Root Dry Weight

SynopsisWe studied the effects of oxygen (aerated versus O2 depleted ∼0.5 mg 1−1 O2) and nitrate (none versus 10 μmol 1−1) on the ammonium uptake kinetics and adenylate pools in two wetland plants differing in their degree of flood tolerance (Phalaris arundinacea L. and Glyceria maxima (Hartm.) Holmb.). The study was performed as a random block design in a growth chamber. The -uptake kinetics were estimated by using a computerised nonlinear parameter estimation procedure to fit the differential form of a modified Michaelis–Menten model to solution depletion curves. The uptake kinetics for differed between the two species: Vmax was significantly higher for P. arundinacea (24.7 to 29.6 μmol h−1 g−1 root dry weight) than for G. maxima (4.6–10.3 μmol h−1 g−1 root dry weight). The concentration at which uptake ceases (Cmin) was 0.2 to 0.5 μmol 1−1 for P. arundinacea and significant higher (1.1–2.7 μmol 1−1) for G. maxima.Km varied between 3.1 and 6.2 μmol 1−1 for P. arundinacea, and 1.6 and 3.0 μmol 1−1 for G. maxima. The different uptake kinetics of the two species reflect the different structure of their root systems: P. arundinacea has an extensive root system consisting of many thin roots whereas G. maxima has fewer but thicker roots. The uptake kinetics also suggest that P. arundinacea is adapted to growing at lower ambient concentrations than G. maxima. Oxygen had no consistent effect on uptake kinetics. However, the plants that had in the nutrient solution as well as had slightly higher Vmax values and lower Cmin and Km values than those without . Thus, both species were able to sustain their uptake characteristics at low external O2 concentrations, probably because of internal aeration through the air-space tissue of the plants. Nitrate deprivation also lowered the energy charge ratio and adenine nucleotide content in roots. The roots recovered quickly from deprivation once was resupplied. The stresses imposed by partially O2-depleted conditions and lack of nitrate were therefore relatively mild and reversible. It seems that the inherent aerenchyma development under aerated conditions in these species is sufficient to maintain adequate root oxygenation under partially O2-depleted conditions.

scholarly journals Labeling of the releasable adenine nucleotides of washed human platelets

Blood ◽  
1977 ◽  
Vol 49 (1) ◽  
pp. 89-99 ◽  
Author(s):  
HJ Reimers ◽  
MA Packham ◽  
JF Mustard
Keyword(s):  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Human Platelets ◽  
Transport Processes ◽  
Adenylate Energy Charge ◽  
Prolonged Incubation ◽  
Atp Pool ◽  
Adenine Nucleotide Pool

Abstract In rabbit platelets, the metabolically active ATP pool equilibrates with the releasable ATP pool within 1 day. The studies showing this have now been extended to human platelets. Human platelets labeled with 14C-adenosine or 14C-adenine were incubated for up to 10 hr in vitro at 37 degrees C. After 10 hr, about 12% of the total platelet 14C-ATP and 14C-ADP had become releasable with thrombin (4.2 units/ml). Lysis of platelets did not occur, since less than 1% of the platelet-bound 51Cr from platelets labeled with this radioisotope appeared in the ambient fluid upon thrombin treatment. The 14C-ATP/14C-ADP ratio of the released adenine nucleotides (7.6) was similar to the 14C-ATP/14C-ADP ratio of the nonreleasable adenine nucleotides (7.1) 2 hr after the labeling with 14C-adenosine. However, upon prolonged incubation (10 hr) in vitro, the 14C-ATP/14C-ADP ratio of the releasable adenine nucleotides decreased to 2.7. The adenylate energy charge and the 14C- ATP/14C-ADP ratio of the metabolic adenine nucleotide pool did not change significantly during the time of observation. The 14C-ATP content of the platelets decreased by less than 1% hr of incubation at 37 degrees C. These observations are interpreted to mean that the 14C is transferred from the metabolically active, nonreleasable adenine nucleotide pool of human platelets into the releasable adenine nucleotide pool as ATP and is partially hydrolyzed there to yield ADP. The transfer of ATP across the storage organelle membrane of platelets may be similar to transport processes in the chromaffin cells of the adrenal medulla and may represent a general phenomenon in cells that possess storage organelles containing adenine nucleotides.

Energy status of the rat lung after exposure to elevated PO2

1978 ◽  
Vol 45 (1) ◽  
pp. 56-59 ◽  
Author(s):  
A. B. Fisher
Keyword(s):  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Rat Lung ◽  
Energy Status ◽  
Hyperoxic Exposure ◽  
Isolated Lung ◽  
Lactate And Pyruvate

To study hyperoxic effects on adenine nucleotide content and lactate and pyruvate production by lungs, rats were exposed to oxygen at 1 ATA for 18, 24, or 48 h or to 4 ATA for 1 h. Subsequently, lungs were removed from rats, placed in an isolated-lung apparatus, ventilated with 5% CO2 in O2, and perfused with Krebs-Ringer bicarbonate medium containing 5.5 mM glucose and 4% bovine serum albumin. Uptake of serotonin from the perfusate was depressed 28% in rats exposed to hyperbaric oxygen compared with unexposed controls. Concentrations of adenine nucleotides, the ATP/ADP ratio, and the “energy charge” were similar in control and oxygen-exposed rats. The production of lactate and the ratio of lactate to pyruvate production were significantly higher in rats exposed to oxygen for 48 h compared with other exposure regimens. Comparison of these results with those previously reported for serotonin uptake in lungs after hyperoxic exposure indicates that serotonin clearance is depressed prior to alteration of the energy status of the rat lung.

Metabolism of adenine nucleotides in the cultured fetal mouse heart

1977 ◽  
Vol 233 (2) ◽  
pp. H282-H288
Author(s):  
I. A. Kaufman ◽  
N. F. Hall ◽  
M. A. DeLuca ◽  
J. S. Ingwall ◽  
S. E. Mayer
Keyword(s):  
Organ Culture ◽  
Adenosine Deaminase ◽  
De Novo ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Mouse Heart ◽  
Nucleotide Synthesis ◽  
Fetal Mouse ◽  
Deprivation Period

Intact beating fetal mouse hearts in organ culture were deprived of oxygen and glucose for up to 4 h, resulting in loss of beating, an 80% fall in ATP, reduction of energy charge from 0.85 to 0.48, and doubling of total nucleoside concentration. Radiolabeled adenine nucleotides were degraded to hypoxanthine and inosine, which were lost from the hearts into the medium during the deprivation period. Adenosine and adenine also appeared in the medium when adenosine deaminase was inhibited. After 24 h of O2 and glucose resupply, ATP returned to 60% of control, and energy charge rose to 0.76. Labeled nucleosides and bases remaining in the heart or exogenous labeled adenine were utilized to resynthesize ATP. [14C]glycine was rapidly taken up by recovering hearts but was not used for de novo adenine nucleotide synthesis. Ability to recover ATP and spontaneous contraction appear related to residual nucleotide and nucleoside content rather than to energy charge.

scholarly journals Adenine nucleotide levels in Rhodospirillum rubrum during switch-off of whole-cell nitrogenase activity

1984 ◽  
Vol 224 (3) ◽  
pp. 961-969 ◽  
Author(s):  
T D Paul ◽  
P W Ludden
Keyword(s):  
Protein Modification ◽  
Rhodospirillum Rubrum ◽  
Adenine Nucleotide ◽  
Nitrogenase Activity ◽  
Energy Charge ◽  
Whole Cell ◽  
Fe Protein ◽  
Nucleotide Pools ◽  
Phenazine Methosulphate

Adenine nucleotide pools were measured in Rhodospirillum rubrum cultures that contained nitrogenase. The average energy charge [([ATP] + 1/2[ADP])/([ATP] + [ADP] + [AMP])] was found to be 0.66 and 0.62 in glutamate-grown and N-limited cultures respectively. Treatment of glutamate-grown cells with darkness, ammonia, glutamine, carbonyl cyanide m-chlorophenylhydrazone, or phenazine methosulphate resulted in perturbations in the adenine nucleotide pools, and led to loss of whole-cell nitrogenase activity and modification in vivo of the Fe protein. Treatment of N-limited cells resulted in similar changes in adenine nucleotide pools but not enzyme modification. No correlations were found between changes in adenine nucleotide pools or ratios of these pools and switch-off of nitrogenase activity by Fe protein modification in vivo. Phenazine methosulphate inhibited whole-cell activity at low concentrations. The effect on nitrogenase activity was apparently independent of Fe protein modification.

Changes in nucleotide pools during conidial germination in Neurospora crassa

1981 ◽  
Vol 59 (11-12) ◽  
pp. 899-905 ◽  
Author(s):  
Richard L. Sabina ◽  
Paulette Dalke ◽  
Alan R. Hanks ◽  
Jane M. Magill ◽  
Clint W. Magill
Keyword(s):  
Neurospora Crassa ◽  
Adenine Nucleotide ◽  
Energy Charge ◽  
Fold Increase ◽  
Conidial Germination ◽  
Adenylate Energy Charge ◽  
Wild Type ◽  
Nucleotide Pools ◽  
Nucleotide Sugars ◽  
Purine Pathway

The acid-soluble nucleotide pools of wild type and several adenine auxotrophs of Neurospora crassa were studied immediately prior to and during conidial germination in the presence of adenine. A two- to four-fold increase in most nucleotide pools was observed after 6 h of germination at 33 °C indicating a general increase in nucleotide pools during this developmental period. The largest components of the acid-soluble nucleotide pools were uracil-containing nucleotide–sugars, which are precursors of chitin and glucan, the major constituents of cell walls. On removal of adenine, the UDP–sugar pools decreased significantly, in adenine auxotrophs, while the pools of UTP increased significantly. ATP levels increased approximately twofold in the first 6 h of germination. After 1 h without exogenous adenine, ATP dropped twofold or more in adenine auxotrophs but not in wild type. There was a net decrease in all adenine nucleotide pools during adenine starvation and a much greater decrease was seen in adenine auxotrophs than in wild type. The adenylate energy charge remained stable despite major changes in the adenylate pools.Accumulation of intermediates was observed in germinated conidia from purine auxotrophs blocked at various steps in the purine pathway. IMP accumulated in ungerminated and in starved conidia of the adenine-8 (ad-8) strain. Ungerminated conidia of the ad-5 strain contained a large pool of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) while the ad-1 strain had smaller amounts of AICAR, but significantly more than any other strain tested. The AICAR pools disappeared from ad-5 and ad-1 in the presence of 50 mg histidine/100 mL. Similarly the IMP pools in ad-8 decreased markedly in the presence of histidine, indicating that the contribution from the histidine biosynthetic pathway to purine nucleotide formation is significant.

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