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.

scholarly journals Evaluation of Usefulness of the Designed Laboratory Photobioreactor for Microalgae Cultivation in Controlled Conditions

2016 ◽  
Vol 20 (1) ◽  
pp. 13-22
Author(s):  
Beata Brzychczyk ◽  
Zbigniew Kowalczyk ◽  
Jan Giełżecki
Keyword(s):  
Culture Medium ◽  
Dry Mass ◽  
Biomass Growth ◽  
Microalgae Cultivation ◽  
Freshwater Microalgae ◽  
Laboratory Conditions ◽  
Medium Concentration ◽  
Controlled Conditions ◽  
The Impact

AbstractThe objective of the paper was to analyse the use of the designed photobioreactor for freshwater microalgae cultivation in the controlled laboratory conditions. The work covered the design and construction of photobioreactors (PBR) and setting up comparative cultivations of freshwater microalgae chlorelli vulgaris along with determination of the biomass growth intensity for a varied amount of supplied culture medium. It was found out that the constructed PBR may be used for microalgae cultivation in the controlled conditions. The impact of the culture medium amount on the growth of chlorelli vulgaris was proved. As a result of the increase of culture medium concentration to 30.1-120.4 ml·l−1 of water, dry mass in photobioreactorsincreased respectively from 1.33 g·dm−3 to 4.68 g·dm−3.

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.

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