Determination of specific oxygen uptake rates in human hematopoietic cultures and implications for bioreactor design

1996 ◽  
Vol 24 (3) ◽  
pp. 373-381 ◽  
Author(s):  
Ching-An Peng ◽  
Bernhard O. Palsson
Keyword(s):  
Oxygen Uptake ◽  
Bioreactor Design ◽  
Uptake Rates

scholarly journals Determination of Oxygen Solubility in Liquid Media

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Francielo Vendruscolo ◽  
Márcio José Rossi ◽  
Willibaldo Schmidell ◽  
Jorge Luiz Ninow
Keyword(s):  
Oxygen Uptake ◽  
Culture Medium ◽  
Accurate Information ◽  
Oxygen Solubility ◽  
Distilled Water ◽  
Monascus Ruber ◽  
Saturation Concentration ◽  
Uptake Rates ◽  
Minimization Of Errors

The present work aimed at determining the oxygen saturation in culture medium used in the production of pigments by Monascus ruber CCT 3802. This estimation allows the correction and the minimization of errors on the specific oxygen uptake rates determination because the conversion of oxygen partial pressure to oxygen concentration requires accurate information on oxygen solubility in experimental incubation media. By adding hydrogen peroxide and then transforming into water and oxygen using catalase, it was possible to determinate the saturation concentration of 7.677 and 6.772 mgO2 L−1 in distilled water and in growth medium, respectively. The determination of these parameters makes possible the minimization of errors on the specific oxygen uptake rates determination, once many studies consider the saturation concentration in distilled water.

scholarly journals Activation-Induced Resetting of Cerebral Oxygen and Glucose Uptake in the Rat

1998 ◽  
Vol 18 (7) ◽  
pp. 742-748 ◽  
Author(s):  
Peter L. Madsen ◽  
Rasmus Linde ◽  
Steen G. Hasselbalch ◽  
Olaf B. Paulson ◽  
Niels A. Lassen
Keyword(s):  
Oxygen Uptake ◽  
Glucose Uptake ◽  
Precise Determination ◽  
Cerebral Oxygen ◽  
Uptake Ratio ◽  
Uptake Rates ◽  
Awake Rat ◽  
Baseline Conditions ◽  
Excess Glucose

In the clinical setting it has been shown that activation will increase cerebral glucose uptake in excess of cerebral oxygen uptake. To study this phenomenon further, this study presents an experimental setup that enables precise determination of the ratio between cerebral uptake of glucose and oxygen in the awake rat. Global CBF was measured by the Kety-Schmidt technique, and the ratio between cerebral uptake rates for oxygen, glucose, and lactate was calculated from cerebral arterial—venous differences. During baseline conditions, rats were kept in a closed box designed to minimize interference. During baseline conditions CBF was 1.08 ± 0.25 mL·g−1·minute−1, and the cerebral oxygen to glucose uptake ratio was 5.5. Activation was induced by opening the sheltering box for 6 minutes. Activation increased CBF to 1.81 mL·g−1·minute−1. During activation cerebral glucose uptake increased disproportionately to cerebral oxygen uptake, and the cerebral oxygen to glucose uptake ratio was 4.2. The accumulated excess glucose uptake during 6 minutes of activation amounted to 2.4 μmol/g. Activation was terminated by closure of the sheltering box. In the postactivation period, the cerebral oxygen to glucose uptake ratio rose to a maximum of 6.4. This response is exactly opposite to the excess cerebral glucose uptake observed during activation.

scholarly journals Kinetic mechanism of Na+-coupled aspartate transport catalyzed by GltTk

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gianluca Trinco ◽  
Valentina Arkhipova ◽  
Alisa A. Garaeva ◽  
Cedric A. J. Hutter ◽  
Markus A. Seeger ◽  
...  
Keyword(s):  
Kinetic Mechanism ◽  
Protein Quantification ◽  
Detergent Solution ◽  
Sodium Ions ◽  
Binding Studies ◽  
Equilibrium Binding ◽  
Uptake Rates ◽  
Bona Fide ◽  
Inside Out

AbstractIt is well-established that the secondary active transporters GltTk and GltPh catalyze coupled uptake of aspartate and three sodium ions, but insight in the kinetic mechanism of transport is fragmentary. Here, we systematically measured aspartate uptake rates in proteoliposomes containing purified GltTk, and derived the rate equation for a mechanism in which two sodium ions bind before and another after aspartate. Re-analysis of existing data on GltPh using this equation allowed for determination of the turnover number (0.14 s−1), without the need for error-prone protein quantification. To overcome the complication that purified transporters may adopt right-side-out or inside-out membrane orientations upon reconstitution, thereby confounding the kinetic analysis, we employed a rapid method using synthetic nanobodies to inactivate one population. Oppositely oriented GltTk proteins showed the same transport kinetics, consistent with the use of an identical gating element on both sides of the membrane. Our work underlines the value of bona fide transport experiments to reveal mechanistic features of Na+-aspartate symport that cannot be observed in detergent solution. Combined with previous pre-equilibrium binding studies, a full kinetic mechanism of structurally characterized aspartate transporters of the SLC1A family is now emerging.

THE METABOLISM OF NORMAL BRAIN AND HUMAN GLIOMAS IN RELATION TO CELL TYPE AND DENSITY

1955 ◽  
Vol 33 (3) ◽  
pp. 395-403 ◽  
Author(s):  
Irving H. Heller ◽  
K. A. C. Elliott
Keyword(s):  
Cerebral Cortex ◽  
White Matter ◽  
Brain Tumors ◽  
Corpus Callosum ◽  
Oxygen Uptake ◽  
Glial Cells ◽  
Cerebellar Cortex ◽  
Unit Weight ◽  
Uptake Rates ◽  
The Brain

Per unit weight, cerebral and cerebellar cortex respire much more actively than corpus callosum. The rate per cell nucleus is highest in cerebral cortex, lower in corpus callosum, and still lower in cerebellar cortex. The oxygen uptake rates of the brain tumors studied, with the exception of an oligodendroglioma, were about the same as that of white matter on the weight basis but lower than that of cerebral cortex or white matter on the cell basis. In agreement with previous work, an oligodendroglioma respired much more actively than the other tumors. The rates of glycolysis of the brain tumors per unit weight were low but, relative to their respiration rate, glycolysis was higher than in normal gray or white matter. Consideration of the figures obtained leads to the following tentative conclusions: Glial cells of corpus callosum respire more actively than the neurons of the cerebellar cortex. Neurons of the cerebral cortex respire on the average much more actively than neurons of the cerebellar cortex or glial cells. Considerably more than 70% of the oxygen uptake by cerebral cortex is due to neurons. The oxygen uptake rates of normal oligodendroglia and astrocytes are probably about the same as the rates found per nucleus in an oligodendroglioma and in astrocytomas; oligodendroglia respire much more actively than astrocytes.

Estimation of bacterial production in fresh waters by the simultaneous measurement of [35S]Sulphate and D-[3H]glucose uptake in the dark

1978 ◽  
Vol 24 (8) ◽  
pp. 939-946 ◽  
Author(s):  
P. G. C. Campbell ◽  
J. H. Baker
Keyword(s):  
Bacterial Production ◽  
Membrane Filter ◽  
Outer Edge ◽  
Size Fractionation ◽  
Sulphate Uptake ◽  
Uptake Rates ◽  
Chalk Stream ◽  
Glucose Assimilation ◽  
Heterotrophic Production

Sulphate uptake in the dark by phytoplankton constitutes a severe limitation to the determination of bacterial heterotrophic production from sulphate-uptake rates. Consequently a modification to the 35S-method has been developed involving size fractionation to separate the algae from the bacteria. Both the whole water sample and the algae-free filtrate are incubated in the dark with trace quantities of [3H]glucose, whereas the filtrate alone is incubated with 35SO4. The experimental determined ratio (whole sample glucose assimilation: filtrate glucose assimilation) is used to correct the measured sulphate uptake (filtrate) and yields an estimate of bacterial sulphate uptake in the whole sample.A potential filtration artefact has been demonstrated in the 35SO4 uptake methodology. Excision of the outer edge of the membrane filter and counting of the inner wetted circle alone eliminated this problem and significantly improved the analytical performance of the method: coefficient of variation ~ 5%, detection limit ~ 2 ng S ℓ−1 h−1. The modified [35SO4]–[3H]-glucose method was applied to samples from an English chalk stream: bacterial sulphate uptake was higher during the spring diatom maximum (10.6 ng S ℓ−1 h−1) than 3 weeks later when detritus dominated the seston (4.9 ng S ℓ−1 h−1). We estimate the corresponding rates of formation of particulate (bacterial) carbon to be 0.53 and 0.24 μg C ℓ−1 h−1 respectively.

A method for measurement of oxygen uptake in neonates

1979 ◽  
Vol 46 (6) ◽  
pp. 1200-1204 ◽  
Author(s):  
D. B. Raemer ◽  
D. R. Westenskow ◽  
D. K. Gehmlich ◽  
C. P. Richardson ◽  
W. S. Jordan
Keyword(s):  
Intensive Care ◽  
Oxygen Uptake ◽  
Positive Airway Pressure ◽  
Animal Experiments ◽  
Newborn Infants ◽  
Positive End Expiratory Pressure ◽  
Newborn Intensive Care Unit ◽  
Frequent Use ◽  
Newborn Intensive Care

The frequent use of continuous positive airway pressure and positive end-expiratory pressure in newborn infants with pulmonary disease has prevented the use of conventional methods for measuring oxygen uptake (VO2) in intensive-care units. A feed-back replenishment technique for the determination of the oxygen uptake of these newborn infants has been developed. An instrument utilizing this method has been designed and built permitting continuous VO2 monitoring without interfering in the routine ventilatory therapy of the critically ill infant. Theoretical, bench, and animal experiments using room air as an inspired gas indicate instrument accuracies as a percentage of full scale of 2.4, 2.8, and 7.3, respectively. Preliminary trials on infants demonstrate that the instrument functions satisfactorily in the newborn intensive-care unit.

Verification phase as a useful tool in the determination of the maximal oxygen uptake of distance runners

2006 ◽  
Vol 31 (5) ◽  
pp. 541-548 ◽  
Author(s):  
Adrian W. Midgley ◽  
Lars R. McNaughton ◽  
Sean Carroll
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Peak Oxygen Uptake ◽  
Treadmill Running ◽  
Distance Runners ◽  
Peak Heart Rate ◽  
Incremental Test ◽  
Volitional Exhaustion

This study investigated the utility of a verification phase for increasing confidence that a “true” maximal oxygen uptake had been elicited in 16 male distance runners (mean age (±SD), 38.7  (± 7.5 y)) during an incremental treadmill running test continued to volitional exhaustion. After the incremental test subjects performed a 10 min recovery walk and a verification phase performed to volitional exhaustion at a running speed 0.5 km·h–1 higher than that attained during the last completed stage of the incremental phase. Verification criteria were a verification phase peak oxygen uptake ≤ 2% higher than the incremental phase value and peak heart rate values within 2 beats·min–1 of each other. Of the 32 tests, 26 satisfied the oxygen uptake verification criterion and 23 satisfied the heart rate verification criterion. Peak heart rate was lower (p = 0.001) during the verification phase than during the incremental phase, suggesting that the verification protocol was inadequate in eliciting maximal values in some runners. This was further supported by the fact that 7 tests exhibited peak oxygen uptake values over 100 mL·min–1 (≥ 3%) lower than the peak values attained in the incremental phase. Further research is required to improve the verification procedure before its utility can be confirmed.

scholarly journals Cultivation at high osmotic pressure confers ubiquinone 8–independent protection of respiration on Escherichia coli

2019 ◽  
Vol 295 (4) ◽  
pp. 981-993 ◽  
Author(s):  
Laura Tempelhagen ◽  
Anita Ayer ◽  
Doreen E. Culham ◽  
Roland Stocker ◽  
Janet M. Wood
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Escherichia Coli ◽  
Electron Transfer ◽  
Oxygen Uptake ◽  
Osmotic Pressure ◽  
Respiratory Chain ◽  
Membrane Lipid ◽  
E Coli ◽  
Uptake Rates

Ubiquinone 8 (coenzyme Q8 or Q8) mediates electron transfer within the aerobic respiratory chain, mitigates oxidative stress, and contributes to gene expression in Escherichia coli. In addition, Q8 was proposed to confer bacterial osmotolerance by accumulating during growth at high osmotic pressure and altering membrane stability. The osmolyte trehalose and membrane lipid cardiolipin accumulate in E. coli cells cultivated at high osmotic pressure. Here, Q8 deficiency impaired E. coli growth at low osmotic pressure and rendered growth osmotically sensitive. The Q8 deficiency impeded cellular O2 uptake and also inhibited the activities of two proton symporters, the osmosensing transporter ProP and the lactose transporter LacY. Q8 supplementation decreased membrane fluidity in liposomes, but did not affect ProP activity in proteoliposomes, which is respiration-independent. Liposomes and proteoliposomes prepared with E. coli lipids were used for these experiments. Similar oxygen uptake rates were observed for bacteria cultivated at low and high osmotic pressures. In contrast, respiration was dramatically inhibited when bacteria grown at the same low osmotic pressure were shifted to high osmotic pressure. Thus, respiration was restored during prolonged growth of E. coli at high osmotic pressure. Of note, bacteria cultivated at low and high osmotic pressures had similar Q8 concentrations. The protection of respiration was neither diminished by cardiolipin deficiency nor conferred by trehalose overproduction during growth at low osmotic pressure, but rather might be achieved by Q8-independent respiratory chain remodeling. We conclude that osmotolerance is conferred through Q8-independent protection of respiration, not by altering physical properties of the membrane.

Engineering aspects of a mixed methanotrophic culture in a membrane-aerated biofilm reactor

2004 ◽  
Vol 49 (11-12) ◽  
pp. 255-262 ◽  
Author(s):  
E. Casey ◽  
S. Rishell ◽  
B. Glennon ◽  
G. Hamer
Keyword(s):  
Oxygen Uptake ◽  
Biofilm Reactor ◽  
Specific Rate ◽  
Suspended Cell ◽  
Biofilm Thickness ◽  
Biofilm Reactors ◽  
Uptake Rates ◽  
Methane Uptake ◽  
Cell Processes ◽  
Oxidation Efficiency

Methanotrophic biodegradation using the membrane-aerated biofilm reactor (MABR) is a technology offering several advantages over both conventional biofilm reactors and suspended-cell processes. In this study the oxidation efficiency of a methanotrophic biofilm in a 1.5 litre MABR was investigated. Measurements of oxygen and methane uptake rates together with biofilm thickness were taken for developing biofilms. It was found that the specific rate of metabolic activity of the biofilm was unusually high as determined by the methane and oxygen uptake rates. Microbial activity stratification was evident and the location of stratified layers of oxygen consuming components of the consortium could be manipulated via the intra-membrane oxygen pressure.

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